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https://www.readbyqxmd.com/read/28922131/riemann-liouvelle-fractional-integral-based-empirical-mode-decomposition-for-ecg-denoising
#1
Shweta Jain, Varun Bajaj, Anil Kumar
Electrocardiograph (ECG) denoising is the most important step in diagnosis of heart related diseases, as the diagnosis gets influenced with noises. In this paper, a new method for ECG denoising is proposed, which incorporates empirical mode decomposition algorithm and Riemann Liouvelle (RL) fractional integral filtering. In the proposed method, noisy ECG signal is decomposed into its intrinsic mode functions (IMFs); from which noisy IMFs are identified by proposed noisy-IMFs identification methodology. RL fractional integral filtering is applied on noisy IMFs to get denoised IMFs; ECG signal is reconstructed with denoised IMFs and remaining signal dominant IMFs to obtain noise-free ECG signal...
September 18, 2017: IEEE Journal of Biomedical and Health Informatics
https://www.readbyqxmd.com/read/28918332/control-of-absence-epilepsy-seizures-in-specific-relay-nuclei-of-thalamus
#2
Bing Hu, Xiaoqiang Zou, Yu Guo, Zhejia Yang, Feng Shi, Wangyuan Dong
In this paper, we used a classic basal ganglia-corticothalamic model(BGCT) to study the onset and control mechanism of absence epilepsy in specific relay nuclei (SRN) of thalamus. It was found that the seizure state may appear in SRN by turning the coupling strength -vsr and signal transmission delay τ on the route "Thalamic reticular nuclei (TRN) of thalamus ⟶ SRN ". With increasing of -vsr, the seizure state appeared two times, and its onset mechanism has not been discussed in previous studies. The seizure activity can be well controlled by adjusting the activation level of the substantia nigra pars reticulata (SNr) in basal ganglia, which is a main output tissue to the corticothalamic system through two direct inhibitory pathways "SNr ⟶ SRN" and "SNr ⟶ TRN " in our model...
September 13, 2017: Journal of Theoretical Biology
https://www.readbyqxmd.com/read/28917659/sonification-of-scalp-recorded-frequency-following-responses-ffrs-offers-improved-response-detection-over-conventional-statistical-metrics
#3
Gavin M Bidelman
BACKGROUND: The human frequency-following response (FFR) is a neurophonic potential used to examine the brain's encoding of complex sounds (e.g., speech) and monitor neuroplastic changes in auditory processing. Given the FFR's low amplitude (order of nanovolts), current conventions in literature recommend collecting several thousand trials to obtain a robust evoked response with adequate signal-to-noise ratio. NEW METHOD: By exploiting the spectrotemporal fidelity of the response, we examined whether auditory playbacks (i...
September 13, 2017: Journal of Neuroscience Methods
https://www.readbyqxmd.com/read/28914753/on-optimal-cooperative-sensing-with-energy-detection-in-cognitive-radio
#4
Sunghwan Bae, Jaewoo So, Hongseok Kim
In this paper, we propose an optimal cooperative sensing technique for cognitive radio to maximize sensing performance based on energy detection. In most spectrum sensing research, many cooperation methods have been proposed to overcome the sensitivity of energy detection so that both primary and secondary users are better off in terms of spectral efficiency. However, without assigning a proper sensing threshold to each sensing node, cooperation may not be effective unless the received average primary user signal-to-noise ratio (SNR) is identical...
September 15, 2017: Sensors
https://www.readbyqxmd.com/read/28913831/asymmetry-between-on-and-off-alpha-ganglion-cells-of-mouse-retina-integration-of-signal-and-noise-from-synaptic-inputs
#5
Michael A Freed
ON and OFF pathways in the retina include functional pairs of neurons that, at first glance, appear to have symmetrically similar responses to brightening and darkening, respectively. Upon careful examination, however, functional pairs exhibit asymmetries in receptive field size and response kinetics. Until now, descriptions of how light-adapted retinal circuitry maintains a preponderance of signal over the noise have not distinguished between ON and OFF pathways. Here I present evidence of marked asymmetries between members of a functional pair of sustained alpha ganglion cells in the mouse retina...
September 15, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28913611/prospective-intraindividual-comparison-of-gadoterate-and-gadobutrol-for-cervical-and-intracranial-contrast-enhanced-magnetic-resonance-angiography
#6
Philip Hoelter, Stefan Lang, Marina Weibart, Manuel Schmidt, Michael F X Knott, Tobias Engelhorn, Marco Essig, Stephan Kloska, Arnd Doerfler
PURPOSE: Gadobutrol (GB) is reported to provide improved relaxivity and concentration compared to gadoterate (GT). This study was designed to intraindividually compare quantitative and qualitative enhancement characteristics of GB to GT in cervicocranial magnetic resonance angiography (MRA) of patients with cerebrovascular disease (CVD). METHODS: Patients (n = 54) with CVD underwent two identical contrast-enhanced magnetic resonance angiography (CE-MRA) examinations of the cervical and intracranial vasculature in randomized order, using GB and GT in equimolar dose...
September 14, 2017: Neuroradiology
https://www.readbyqxmd.com/read/28912671/brownian-optogenetic-noise-photostimulation-on-the-brain-amplifies-somatosensory-evoked-field-potentials
#7
Nayeli Huidobro, Abraham Mendez-Fernandez, Ignacio Mendez-Balbuena, Ranier Gutierrez, Rumyana Kristeva, Elias Manjarrez
Stochastic resonance (SR) is an inherent and counter-intuitive mechanism of signal-to-noise ratio (SNR) facilitation in biological systems associated with the application of an intermediate level of noise. As a first step to investigate in detail this phenomenon in the somatosensory system, here we examined whether the direct application of noisy light on pyramidal neurons from the mouse-barrel cortex expressing a light-gated channel channelrhodopsin-2 (ChR2) can produce facilitation in somatosensory evoked field potentials...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28910689/numerical-simulation-of-endoscopic-magnetoacoustic-tomography-with-magnetic-induction
#8
Sun Zheng, Ma Zhen
Endoscopic magnetoacoustic tomography with magnetic induction (EMAT-MI) provides an interventional tool to detect the electrical conductivity distribution of a tubular structure with high spatial resolution. In this work, a preliminary study on the numerical simulation of EMAT-MI images was conducted. The magnetic excitation, generation and propagation of magnetoacoustic (MA) waves in the multi-layered wall tissues were modeled and numerically simulated. The cross-sectional distribution of the acoustic source and electrical conductivity was recovered from the acoustic pressure series based on time-reversal...
September 6, 2017: Computers in Biology and Medicine
https://www.readbyqxmd.com/read/28906240/listening-effort-measured-in-adults-with-normal-hearing-and-cochlear-implants
#9
Ann E Perreau, Yu-Hsiang Wu, Bailey Tatge, Diana Irwin, Daniel Corts
BACKGROUND: Studies have examined listening effort in individuals with hearing loss to determine the extent of the impairment. Regarding cochlear implants (CIs), results suggest that listening effort is improved using bilateral CIs compared to unilateral CIs. Few studies have investigated listening effort and outcomes related to the hybrid CI. PURPOSE: Here, we compared listening effort across three CI groups, and to a normal-hearing control group. The impact of listener traits, that is, age, age at onset of hearing loss, duration of CI use, and working memory capacity, were examined relative to listening effort...
September 2017: Journal of the American Academy of Audiology
https://www.readbyqxmd.com/read/28905812/carbon-fiber-on-polyimide-ultra-microelectrodes
#10
Wintrop F Gillis, Charles A Lissandrello, Jun Shen, Ben W Pearre, Alket Mertiri, Felix Deku, Stuart Cogan, Bradley J Holinski, Daniel J Chew, Alice E White, Timothy M Otchy, Timothy Gardner
OBJECTIVE: Most preparations for making neural recordings degrade over time and eventually fail due to insertion trauma and reactive tissue response. The magnitudes of these responses are thought to be related to the electrode size (specifically, the cross-sectional area), the relative stiffness of the electrode, and the degree of tissue tolerance for the material. Flexible carbon fiber ultra-microelectrodes have a much smaller cross-section than traditional electrodes and low tissue reactivity, and thus may enable improved longevity of neural recordings in the central and peripheral nervous systems...
September 14, 2017: Journal of Neural Engineering
https://www.readbyqxmd.com/read/28905416/sar-and-scan-time-optimized-3d-whole-brain-double-inversion-recovery-imaging-at-7t
#11
Eberhard D Pracht, Thorsten Feiweier, Philipp Ehses, Daniel Brenner, Alard Roebroeck, Bernd Weber, Tony Stöcker
PURPOSE: The aim of this project was to implement an ultra-high field (UHF) optimized double inversion recovery (DIR) sequence for gray matter (GM) imaging, enabling whole brain coverage in short acquisition times ( ≈5 min, image resolution 1 mm(3) ). METHODS: A 3D variable flip angle DIR turbo spin echo (TSE) sequence was optimized for UHF application. We implemented an improved, fast, and specific absorption rate (SAR) efficient TSE imaging module, utilizing improved reordering...
September 14, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28905414/high-spatio-temporal-resolution-in-functional-mri-with-3d-echo-planar-imaging-using-cylindrical-excitation-and-a-caipirinha-undersampling-pattern
#12
Wietske van der Zwaag, Olivier Reynaud, Mayur Narsude, Daniel Gallichan, José P Marques
PURPOSE: The combination of 3D echo planar imaging (3D-EPI) with a 2D-CAIPIRINHA undersampling scheme provides high flexibility in the optimization for spatial or temporal resolution. This flexibility can be increased further with the addition of a cylindrical excitation pulse, which exclusively excites the brain regions of interest. Here, 3D-EPI was combined with a 2D radiofrequency pulse to reduce the brain area from which signal is generated, and hence, allowing either reduction of the field of view or reduction of parallel imaging noise amplification...
September 14, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28902988/improvement-of-lod-in-fluorescence-detection-with-spectrally-non-uniform-background-by-optimization-of-emission-filtering
#13
Victor A Galievsky, Alexander S Stasheuski, Sergey N Krylov
The limit-of-detection (LOD) in analytical instruments with fluorescence detection can be improved by reducing noise of optical background. Efficiently reducing optical background noise in systems with spectrally non-uniform background requires complex optimization of an emission filter - the main element of spectral filtration. Here we introduce a filter-optimization method which utilizes an expression for the signal-to-noise ratio (SNR) as a function of (i) all noise components (dark, shot, and flicker), (ii) emission spectrum of the analyte, (iii) emission spectrum of the optical background, and (iv) transmittance spectrum of the emission filter...
September 13, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28901609/adaptive-non-local-means-on-local-principle-neighborhood-for-noise-artifacts-reduction-in-low-dose-ct-images
#14
Yuanke Zhang, Hongbing Lu, Junyan Rong, Jing Meng, Junliang Shang, Pinghong Ren, Junying Zhang
PURPOSE: Low-dose CT (LDCT) technique can reduce the x-ray radiation exposure to patients at the cost of degraded images with severe noise and artifacts. Non-local means (NLM) filtering has shown its potential in improving LDCT image quality. However, currently most NLM-based approaches employ a weighted average operation directly on all neighbor pixels with a fixed filtering parameter throughout the NLM filtering process, ignoring the non-stationary noise nature of LDCT images. In this paper, an adaptive NLM filtering scheme on local principle neighborhoods (PC-NLM) is proposed for structure-preserving noise/artifacts reduction in LDCT images...
September 2017: Medical Physics
https://www.readbyqxmd.com/read/28899573/split-spectrum-processing-technique-for-snr-enhancement-of-ultrasonic-guided-wave
#15
Seyed Kamran Pedram, Sina Fateri, Lu Gan, Alex Haig, Keith Thornicroft
Ultrasonic guided wave (UGW) systems are broadly used in several branches of industry where the structural integrity is of concern. In those systems, signal interpretation can often be challenging due to the multi-modal and dispersive propagation of UGWs. This results in degradation of the signals in terms of signal-to-noise ratio (SNR) and spatial resolution. This paper employs the split-spectrum processing (SSP) technique in order to enhance the SNR and spatial resolution of UGW signals using the optimized filter bank parameters in real time scenario for pipe inspection...
August 24, 2017: Ultrasonics
https://www.readbyqxmd.com/read/28899377/quantitative-magnetic-resonance-imaging-mri-analysis-of-anterior-talofibular-ligament-in-lateral-chronic-ankle-instability-ankles-pre-and-postoperatively
#16
Wei Liu, Hong Li, Yinghui Hua
BACKGROUND: The aim of this study was to quantitatively evaluate and characterize the dimension and signal intensity of anterior talofibular ligament (ATFL) using 3.0 T MRI in the mechanical ankle instability group pre- and postoperatively. METHODS: A total of 97 participants were recruited retrospectively in this study, including 56 with mechanical chronic ankle instability (CAI group) and 41 without ankle instability (Control group). All the subjects accepted MRI preoperatively...
September 12, 2017: BMC Musculoskeletal Disorders
https://www.readbyqxmd.com/read/28894328/comparison-of-cartesian-and-radial-acquisition-on-short-tau-inversion-recovery-stir-sequences-in-breast-mri
#17
Domiziana Santucci, Sheila S Lee, Heidi Hartman, Shyama Walgampaya, Mamdoh AlObaidy, Miguel Ramalho, Brian M Dale, Richard C Semelka
OBJECTIVE: The purpose of this study was to compare two short-tau inversion recovery (STIR) sequences, Cartesian and radial (BLADE) acquisitions, for breast magnetic resonance imaging (MRI) examinations. MATERIALS AND METHODS: Ninety-six women underwent 1.5 T breast MRI exam (48 Cartesian and 48 BLADE). Qualitative analysis including image artifacts, image quality, fat-suppression, chest-wall depiction, lesion detection, lymph node depiction and overall impression were evaluated by three blinded readers...
July 2017: Radiologia Brasileira
https://www.readbyqxmd.com/read/28893075/classroom-acoustics-as-a-consideration-for-inclusive-education-in-south-africa
#18
Coralie Van Reenen, Catherine Karusseit
BACKGROUND: It can hardly be disputed that a school environment should be conducive or, at the very least, not prohibitive to effective learning. The provision of fair, equal and barrier-free access to education is referred to as inclusive education. South Africa supports a policy of inclusive schooling, striving to accommodate all children, including those with disabilities, in mainstream schools. This article sets out to prove that noise control in classrooms is a relevant, yet neglected, aspect of inclusive classroom design in South Africa and requires specific attention...
September 8, 2017: South African Journal of Communication Disorders. die Suid-Afrikaanse Tydskrif Vir Kommunikasieafwykings
https://www.readbyqxmd.com/read/28891927/differential-cmos-sub-terahertz-detector-with-subthreshold-amplifier
#19
Jong-Ryul Yang, Seong-Tae Han, Donghyun Baek
We propose a differential-type complementary metal-oxide-semiconductor (CMOS) sub-terahertz (THz) detector with a subthreshold preamplifier. The proposed detector improves the voltage responsivity and effective signal-to-noise ratio (SNR) using the subthreshold preamplifier, which is located between the differential detector device and main amplifier. The overall noise of the detector for the THz imaging system is reduced by the preamplifier because it diminishes the noise contribution of the main amplifier...
September 9, 2017: Sensors
https://www.readbyqxmd.com/read/28888891/investigating-the-role-of-temporal-lobe-activation-in-speech-perception-accuracy-with-normal-hearing-adults-an-event-related-fnirs-study
#20
Jessica Defenderfer, Anastasia Kerr-German, Mark Hedrick, Aaron T Buss
Functional near infrared spectroscopy (fNIRS) is a safe, non-invasive, relatively quiet imaging technique that is tolerant of movement artifact making it uniquely ideal for the assessment of hearing mechanisms. Previous research demonstrates the capacity for fNIRS to detect cortical changes to varying speech intelligibility, revealing a positive relationship between cortical activation amplitude and speech perception score. In the present study, we use an event-related design to investigate the hemodynamic response in the temporal lobe across different listening conditions...
September 6, 2017: Neuropsychologia
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