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https://www.readbyqxmd.com/read/28642679/assessment-of-ipsilateral-efferent-effects-in-human-via-ecochg
#1
Eric Verschooten, Elizabeth A Strickland, Nicolas Verhaert, Philip X Joris
Development of electrophysiological means to assess the medial olivocochlear (MOC) system in humans is important to further our understanding of the function of that system and for the refinement and validation of psychoacoustical and otoacoustic emission methods which are thought to probe the MOC. Based on measurements in anesthetized animals it has been hypothesized that the MOC-reflex (MOCR) can enhance the response to signals in noise, and several lines of evidence support such a role in humans. A difficulty in these studies is the isolation of efferent effects...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28641435/validating-and-implementing-modified-filinov-phase-filtration-in-semiclassical-dynamics
#2
Matthew S Church, Sergey V Antipov, Nandini Ananth
The Mixed Quantum-Classical Initial Value Representation (MQC-IVR) is a recently introduced approximate semiclassical (SC) method for the calculation of real-time quantum correlation functions. MQC-IVR employs a modified Filinov filtration (MFF) scheme to control the overall phase of the SC integrand, extending the applicability of SC methods to complex systems while retaining their ability to accurately describe quantum coherence effects. Here, we address questions regarding the effectiveness of the MFF scheme in combination with SC dynamics...
June 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28641265/a-new-method-for-neural-spike-alignment-the-centroid-filter
#3
Benjamin Metcalfe, Chris Clarke, Nick Donaldson, John Taylor
Recordings made directly from the nervous system are a key tool in experimental electrophysiology and the development of bioelectronic medicines. Analysis of these recordings involves the identification of signals from individual neurons, a process known as spike sorting. A critical and limiting feature of spike sorting is the need to align individual spikes in time. However, electrophysiological recordings are made in extremely noisy environments that seriously limit the performance of the spike-alignment process...
June 16, 2017: IEEE Transactions on Neural Systems and Rehabilitation Engineering
https://www.readbyqxmd.com/read/28641248/method-for-simulating-dose-reduction-in-digital-breast-tomosynthesis
#4
Lucas R Borges, Igor Guerrero, Predrag R Bakic, Alessandro Foi, Andrew D A Maidment, Marcelo A C Vieira
This work proposes a new method of simulating dose reduction in digital breast tomosynthesis (DBT), starting from a clinical image acquired with a standard radiation dose. It considers both signal-dependent quantum and signal-independent electronic noise. Furthermore, the method accounts for pixel crosstalk, which causes the noise to be frequency-dependent, thus increasing the simulation accuracy. For an objective assessment, simulated and real images were compared in terms of noise standard deviation, signal-to-noise ratio (SNR) and normalized noise power spectrum (NNPS)...
June 15, 2017: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28640821/noise-reduction-in-single-time-frame-optical-dna-maps
#5
Paola C Torche, Vilhelm Müller, Fredrik Westerlund, Tobias Ambjörnsson
In optical DNA mapping technologies sequence-specific intensity variations (DNA barcodes) along stretched and stained DNA molecules are produced. These "fingerprints" of the underlying DNA sequence have a resolution of the order one kilobasepairs and the stretching of the DNA molecules are performed by surface adsorption or nano-channel setups. A post-processing challenge for nano-channel based methods, due to local and global random movement of the DNA molecule during imaging, is how to align different time frames in order to produce reproducible time-averaged DNA barcodes...
2017: PloS One
https://www.readbyqxmd.com/read/28640038/impact-of-noise-and-noise-reduction-on-processing-effort-a-pupillometry-study
#6
Dorothea Wendt, Renskje K Hietkamp, Thomas Lunner
OBJECTIVES: Speech perception in adverse listening situations can be exhausting. Hearing loss particularly affects processing demands, as it requires increased effort for successful speech perception in background noise. Signal processing in hearing aids and noise reduction (NR) schemes aim to counteract the effect of noise and reduce the effort required for speech recognition in adverse listening situations. The present study examined the benefit of NR schemes, applying a combination of a digital NR and directional microphones, for reducing the processing effort during speech recognition...
June 20, 2017: Ear and Hearing
https://www.readbyqxmd.com/read/28637959/examination-of-dose-reduction-using-image-noise-reduction-technology-in-cardiovascular-x-ray-systems
#7
Takaya Saijo, Shigenobu Seguchi
The aim of this study is to establish radiation exposure dose reduction protocols during cardiac intervention by decreasing the entrance dose at flat panel detector (FPD) with image quality evaluations. For measuring entrance surface dose (ESD), we have used a Radical 9015 dosimeter (6 cc ion chamber) placed under 20 cm thick acrylic plates at the patient's entrance reference point. We performed an image quality assessment based on quantitative as well as visual evaluation of the images obtained via current and dose reduction protocols...
2017: Nihon Hoshasen Gijutsu Gakkai Zasshi
https://www.readbyqxmd.com/read/28637508/hyperpolarized-13-c-urea-myocardial-first-pass-perfusion-imaging-using-velocity-selective-excitation
#8
Maximilian Fuetterer, Julia Busch, Sophie M Peereboom, Constantin von Deuster, Lukas Wissmann, Miriam Lipiski, Thea Fleischmann, Nikola Cesarovic, Christian T Stoeck, Sebastian Kozerke
BACKGROUND: A velocity-selective binomial excitation scheme for myocardial first-pass perfusion measurements with hyperpolarized (13)C substrates, which preserves bolus magnetization inside the blood pool, is presented. The proposed method is evaluated against gadolinium-enhanced (1)H measurements in-vivo. METHODS: The proposed excitation with an echo-planar imaging readout was implemented on a clinical CMR system. Dynamic myocardial stress perfusion images were acquired in six healthy pigs after bolus injection of hyperpolarized (13)C urea with the velocity-selective vs...
June 21, 2017: Journal of Cardiovascular Magnetic Resonance
https://www.readbyqxmd.com/read/28632205/speckle-modulating-optical-coherence-tomography-in-living-mice-and-humans
#9
Orly Liba, Matthew D Lew, Elliott D SoRelle, Rebecca Dutta, Debasish Sen, Darius M Moshfeghi, Steven Chu, Adam de la Zerda
Optical coherence tomography (OCT) is a powerful biomedical imaging technology that relies on the coherent detection of backscattered light to image tissue morphology in vivo. As a consequence, OCT is susceptible to coherent noise (speckle noise), which imposes significant limitations on its diagnostic capabilities. Here we show speckle-modulating OCT (SM-OCT), a method based purely on light manipulation that virtually eliminates speckle noise originating from a sample. SM-OCT accomplishes this by creating and averaging an unlimited number of scans with uncorrelated speckle patterns without compromising spatial resolution...
June 20, 2017: Nature Communications
https://www.readbyqxmd.com/read/28629567/ct-coronary-calcium-scoring-with-tin-filtration-using-iterative-beam-hardening-calcium-correction-reconstruction
#10
Christian Tesche, Carlo N De Cecco, U Joseph Schoepf, Taylor M Duguay, Moritz H Albrecht, Domenico De Santis, Akos Varga-Szemes, Virginia W Lesslie, Ullrich Ebersberger, Richard R Bayer, Christian Canstein, Ellen Hoffmann, Thomas Allmendinger, John W Nance
OBJECTIVES: To investigate the diagnostic accuracy of CT coronary artery calcium scoring (CACS) with tin pre-filtration (Sn100kVp) using iterative beam-hardening correction (IBHC) calcium material reconstruction compared to the standard 120kVp acquisition. BACKGROUND: Third generation dual-source CT (DSCT) CACS with Sn100kVp acquisition allows significant dose reduction. However, the Sn100kVp spectrum is harder with lower contrast compared to 120kVp, resulting in lower calcium score values...
June 2017: European Journal of Radiology
https://www.readbyqxmd.com/read/28629154/two-novel-two-stage-direction-of-arrival-estimation-algorithms-for-two-dimensional-mixed-noncircular-and-circular-sources
#11
Heping Shi, Wen Leng, Zhiwei Guan, Tongzhi Jin
This paper addresses the two-dimensional (2D) direction-of-arrival (DOA) estimation problem with two novel methods for mixed noncircular and circular signals. The first proposed method is named the two-stage direction-of-arrival matrix (TSDOAM) method, and the other is called the two-stage rank reduction (TSRARE) method. The proposed methods utilize both the circularity and the direction-of-arrival differences between the noncircular and circular sources to estimate the 2D directions-of-arrival (DOAs). The maximum detectable 2D angle parameters of the TSDOAM and TSRARE methods are twice those of the existing methods...
June 18, 2017: Sensors
https://www.readbyqxmd.com/read/28622678/robust-least-squares-support-vector-machine-with-minimization-of-mean-and-variance-of-modeling-error
#12
Xinjiang Lu, Wenbo Liu, Chuang Zhou, Minghui Huang
The least-squares support vector machine (LS-SVM) is a popular data-driven modeling method and has been successfully applied to a wide range of applications. However, it has some disadvantages, including being ineffective at handling non-Gaussian noise as well as being sensitive to outliers. In this paper, a robust LS-SVM method is proposed and is shown to have more reliable performance when modeling a nonlinear system under conditions where Gaussian or non-Gaussian noise is present. The construction of a new objective function allows for a reduction of the mean of the modeling error as well as the minimization of its variance, and it does not constrain the mean of the modeling error to zero...
June 13, 2017: IEEE Transactions on Neural Networks and Learning Systems
https://www.readbyqxmd.com/read/28622587/statistical-characterization-of-noise-for-spatial-standardization-of-ct-scans-enabling-comparison-with-multiple-kernels-and-doses
#13
Gonzalo Vegas-Sánchez-Ferrero, Maria J Ledesma-Carbayo, George R Washko, Raúl San José Estépar
Computerized tomography (CT) is a widely adopted modality for analyzing directly or indirectly functional, biological and morphological processes by means of the image characteristics. However, the potential utilization of the information obtained from CT images is often limited when considering the analysis of quantitative information involving different devices, acquisition protocols or reconstruction algorithms. Although CT scanners are calibrated as a part of the imaging workflow, the calibration is circumscribed to global reference values and does not circumvent problems that are inherent to the imaging modality...
June 7, 2017: Medical Image Analysis
https://www.readbyqxmd.com/read/28620616/the-impact-of-combining-a-low-tube-voltage-acquisition-with-iterative-reconstruction-on-total-iodine-dose-in-coronary-ct-angiography
#14
Toon Van Cauteren, Gert Van Gompel, Kaoru Tanaka, Douwe E Verdries, Dries Belsack, Koenraad H Nieboer, Inneke Willekens, Paul Evans, Sven Macholl, Guy Verfaillie, Steven Droogmans, Johan de Mey, Nico Buls
OBJECTIVES: To assess the impact of combining low-tube voltage acquisition with iterative reconstruction (IR) techniques on the iodine dose in coronary CTA. METHODS: Three minipigs underwent CCTA to compare a standard of care protocol with two alternative study protocols combining low-tube voltage and low iodine dose with IR. Image quality was evaluated objectively by the CT value, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) in the main coronary arteries and aorta and subjectively by expert reading...
2017: BioMed Research International
https://www.readbyqxmd.com/read/28618816/test-of-single-degree-of-freedom-acoustic-treatment-impedance-models-for-multimodal-acoustic-propagation-in-duct-with-flow
#15
Ryan Baccouche, Soléne Moreau, Mabrouk Ben Tahar
Passive acoustic treatments, also called liners, are the main solution to noise problems. The Single Degree Of Freedom (SDOF) acoustic treatment, composed of a thin material (perforated plate) affixed to air cavities with a rigid bottom, constitutes a solution. Predicting sound level reduction by an SDOF treatment requires reliable acoustic impedance models. An experimental/numerical method has been developed for a duct with an acoustic treatment to test acoustic impedance models of SDOF treatment with a multimodal propagation in the presence of a mean flow...
June 2017: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/28618803/effects-of-linear-and-nonlinear-speech-rate-changes-on-speech-intelligibility-in-stationary-and-fluctuating-maskers
#16
Martin Cooke, Vincent Aubanel
Algorithmic modifications to the durational structure of speech designed to avoid intervals of intense masking lead to increases in intelligibility, but the basis for such gains is not clear. The current study addressed the possibility that the reduced information load produced by speech rate slowing might explain some or all of the benefits of durational modifications. The study also investigated the influence of masker stationarity on the effectiveness of durational changes. Listeners identified keywords in sentences that had undergone linear and nonlinear speech rate changes resulting in overall temporal lengthening in the presence of stationary and fluctuating maskers...
June 2017: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/28618295/phase-locked-and-non-phase-locked-eeg-responses-to-pinprick-stimulation-before-and-after-experimentally-induced-secondary-hyperalgesia
#17
Emanuel N van den Broeke, Bart de Vries, Julien Lambert, Diana M Torta, André Mouraux
OBJECTIVE: Pinprick-evoked brain potentials (PEPs) have been proposed as a technique to investigate secondary hyperalgesia and central sensitization in humans. However, the signal-to-noise (SNR) of PEPs is low. Here, using time-frequency analysis, we characterize the phase-locked and non-phase-locked EEG responses to pinprick stimulation, before and after secondary hyperalgesia. METHODS: Secondary hyperalgesia was induced using high-frequency electrical stimulation (HFS) of the left/right forearm skin in 16 volunteers...
May 19, 2017: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/28617642/extinction-risk-and-lack-of-evolutionary-rescue-under-resource-depletion-or-area-reduction
#18
Steinar Engen, Bernt-Erik Sæther
Evolutionary adaptations following environmental deterioration can sometimes rescue populations from extinction. Here we provide a scenario in which such evolutionary rescue will be difficult. Using a rather general model for fluctuating r- and K-selection in a density-dependent population, we show that reduction of available resources will not necessarily induce evolution of adaptations to counteract such changes provided that density regulation acts through available resources per individual. In large populations, resource depletion may induce a change in stationary distribution of population size while the optimal phenotype remains unchanged...
July 2017: American Naturalist
https://www.readbyqxmd.com/read/28617421/a-targeted-noise-reduction-observational-study-for-reducing-noise-in-a-neonatal-intensive-unit
#19
S Chawla, P Barach, M Dwaihy, D Kamat, S Shankaran, B Panaitescu, B Wang, G Natarajan
BACKGROUND: Excessive noise in neonatal intensive care units (NICUs) can interfere with infants' growth, development and healing.Local problem:Sound levels in our NICUs exceeded the recommended levels by the World Health Organization. METHODS: We implemented a noise reduction strategy in an urban, tertiary academic medical center NICU that included baseline noise measurements. We conducted a survey involving staff and visitors regarding their opinions and perceptions of noise levels in the NICU...
June 15, 2017: Journal of Perinatology: Official Journal of the California Perinatal Association
https://www.readbyqxmd.com/read/28614315/single-shot-coherent-noise-suppression-by-spatial-interferometric-heterodyning
#20
Milad I Akhlaghi, Aristide Dogariu
Coherent noise affects the information content in active imaging systems. Here we show that noise reduction can be accomplished using the intrinsic coherence properties of the electromagnetic fields. We demonstrate numerically and experimentally that a single-shot measurement using interferometric spatial heterodyning detection in conjuncture with computational image processing, permits suppressing coherent noise in conditions of low signal-to-noise ratios, through spectral upshifting of coherent information...
June 15, 2017: Optics Letters
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