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https://www.readbyqxmd.com/read/29786862/experimental-fluence-modulated-proton-computed-tomography-by-pencil-beam-scanning
#1
George Dedes, Robert P Johnson, Mark Pankuch, Nick Detrich, Willemijn M A Pols, Simon Rit, Reinhard W Schulte, Katia Parodi, Guillaume Landry
PURPOSE: This experimental study is aimed at demonstrating, using a simple cylindrical water phantom, the feasibility of fluence modulated proton computed tomography (FMpCT) by pencil beam scanning (PBS) proton computed tomography (pCT). METHODS: The phase II pCT prototype of the Loma Linda U. and U. C. Santa Cruz was operated using the PBS beam line of the Northwestern Medicine Chicago Proton Center. A 20x10 grid of 1.37 cm full width half maximum pencil beams (PB) equally spaced by 1 cm was used to acquire 45 projections in step and shoot mode...
May 22, 2018: Medical Physics
https://www.readbyqxmd.com/read/29785972/a-methodology-to-objectively-assess-the-performance-of-sound-field-amplification-systems-demonstrated-using-50-physical-simulations-of-classroom-conditions
#2
Stephen Dance, Bradford Backus, Lorenzo Morales
Introduction: The effect of a sound reinforcement system, in terms of speech intelligibility, has been systematically determined under realistic conditions. Different combinations of ambient and reverberant conditions representative of a classroom environment have been investigated. Materials and Methods: By comparing the measured speech transmission index metric with and without the system in the same space under different room acoustics conditions, it was possible to determine when the system was most effective...
May 2018: Noise & Health
https://www.readbyqxmd.com/read/29780971/acquisition-of-bioelectrical-signals-with-small-electrodes
#3
Vijay Viswam, Marie Obien, Urs Frey, Felix Franke, Andreas Hierlemann
Although the mechanisms of recording bioelectrical signals from different types of electrogenic cells (neurons, cardiac cells etc.) by means of planar metal electrodes have been extensively studied, the recording characteristics and conditions for very small electrode sizes are not yet established. Here, we present a combined experimental and computational approach to elucidate, how the electrode size influences the recorded signals, and how inherent properties of the electrode, such as impedance, noise, and transmission characteristics shape the signal...
March 29, 2018: IEEE Biomedical Circuits and Systems Conference: Healthcare Technology: [proceedings]
https://www.readbyqxmd.com/read/29780296/metal-artifact-reduction-for-orthopedic-implants-brain-ct-angiography-in-patients-with-intracranial-metallic-implants
#4
Leonard Sunwoo, Sun-Won Park, Jung Hyo Rhim, Yeonah Kang, Young Seob Chung, Young-Je Son, Soo Chin Kim
Background: The purpose of this study was to qualitatively and quantitatively evaluate the effects of a metal artifact reduction for orthopedic implants (O-MAR) for brain computed tomographic angiography (CTA) in patients with aneurysm clips and coils. Methods: The study included 36 consecutive patients with 47 intracranial metallic implants (42 aneurysm clips, 5 coils) who underwent brain CTA. The computed tomographic images with and without the O-MAR were independently reviewed both quantitatively and qualitatively by two reviewers...
May 21, 2018: Journal of Korean Medical Science
https://www.readbyqxmd.com/read/29779607/impact-of-snr-masker-type-and-noise-reduction-processing-on-sentence-recognition-performance-and-listening-effort-as-indicated-by-the-pupil-dilation-response
#5
Barbara Ohlenforst, Dorothea Wendt, Sophia E Kramer, Graham Naylor, Adriana A Zekveld, Thomas Lunner
Recent studies have shown that activating the noise reduction scheme in hearing aids results in a smaller peak pupil dilation (PPD), indicating reduced listening effort, at 50% and 95% correct sentence recognition with a 4-talker masker. The objective of this study was to measure the effect of the noise reduction scheme (on or off) on PPD and sentence recognition across a wide range of signal-to-noise ratios (SNRs) from +16 dB to -12 dB and two masker types (4-talker and stationary noise). Relatively low PPDs were observed at very low (-12 dB) and very high (+16 dB to +8 dB) SNRs presumably due to 'giving up' and 'easy listening', respectively...
May 6, 2018: Hearing Research
https://www.readbyqxmd.com/read/29774974/stiffness-reconstruction-methods-for-mr-elastography
#6
Daniel Fovargue, David Nordsletten, Ralph Sinkus
Assessment of tissue stiffness is desirable for clinicians and researchers, as it is well established that pathophysiological mechanisms often alter the structural properties of tissue. Magnetic resonance elastography (MRE) provides an avenue for measuring tissue stiffness and has a long history of clinical application, including staging liver fibrosis and stratifying breast cancer malignancy. A vital component of MRE consists of the reconstruction algorithms used to derive stiffness from wave-motion images by solving inverse problems...
May 18, 2018: NMR in Biomedicine
https://www.readbyqxmd.com/read/29773471/increased-spontaneous-firing-rates-in-auditory-midbrain-following-noise-exposure-are-specifically-abolished-by-a-kv3-channel-modulator
#7
Lucy A Anderson, Lara L Hesse, Nadia Pilati, Warren M H Bakay, Giuseppe Alvaro, Charles H Large, David McAlpine, Roland Schaette, Jennifer F Linden
Noise exposure has been shown to produce long-lasting increases in spontaneous activity in central auditory structures in animal models, and similar pathologies are thought to contribute to clinical phenomena such as hyperacusis or tinnitus in humans. Here we demonstrate that multi-unit spontaneous neuronal activity in the inferior colliculus (IC) of mice is significantly elevated four weeks following noise exposure at recording sites with frequency tuning within or near the noise exposure band, and this selective central auditory pathology can be normalised through administration of a novel compound that modulates activity of Kv3 voltage-gated ion channels...
April 30, 2018: Hearing Research
https://www.readbyqxmd.com/read/29768380/tradeoff-between-noise-reduction-and-inartificial-visualization-in-a-model-based-iterative-reconstruction-algorithm-on-coronary-computed-tomography-angiography
#8
Kenichiro Hirata, Daisuke Utsunomiya, Masafumi Kidoh, Yoshinori Funama, Seitaro Oda, Hideaki Yuki, Yasunori Nagayama, Yuji Iyama, Takeshi Nakaura, Daisuke Sakabe, Kenichi Tsujita, Yasuyuki Yamashita
We aimed to evaluate the image quality performance of coronary CT angiography (CTA) under the different settings of forward-projected model-based iterative reconstruction solutions (FIRST).Thirty patients undergoing coronary CTA were included. Each image was reconstructed using filtered back projection (FBP), adaptive iterative dose reduction 3D (AIDR-3D), and 2 model-based iterative reconstructions including FIRST-body and FIRST-cardiac sharp (CS). CT number and noise were measured in the coronary vessels and plaque...
May 2018: Medicine (Baltimore)
https://www.readbyqxmd.com/read/29767336/-contribution-of-natural-spaces-to-human-health-and-wellbeing
#9
REVIEW
Thomas Claßen, Maxie Bunz
Natural spaces and especially urban green and blue spaces have been recognised for a long time as spaces with great potential for protecting and promoting human health and well-being. They may affect human physical, mental and social health and well-being in various ways. On one hand, this comes to pass through reduction and moderation of potential environmental health risks (e. g. noise, particulate matter, heat), psycho-physiological effects of nature experience, as well as physical effects of exposure to natural compounds and elements...
May 16, 2018: Bundesgesundheitsblatt, Gesundheitsforschung, Gesundheitsschutz
https://www.readbyqxmd.com/read/29759684/how-aging-impacts-the-encoding-of-binaural-cues-and-the-perception-of-auditory-space
#10
REVIEW
Ann Clock Eddins, Erol J Ozmeral, David A Eddins
Over the years, the effect of aging on auditory function has been investigated in animal models and humans in an effort to characterize age-related changes in both perception and physiology. Here, we review how aging may impact neural encoding and processing of binaural and spatial cues in human listeners with a focus on recent work by the authors as well as others. Age-related declines in monaural temporal processing, as estimated from measures of gap detection and temporal fine structure discrimination, have been associated with poorer performance on binaural tasks that require precise temporal processing...
May 5, 2018: Hearing Research
https://www.readbyqxmd.com/read/29759649/using-pattern-recognition-entropy-to-select-mass-chromatograms-to-prepare-total-ion-current-chromatograms-from-raw-liquid-chromatography-mass-spectrometry-data
#11
Shiladitya Chatterjee, George H Major, Brett Paull, Estrella Sanz Rodriguez, Massoud Kaykhaii, Matthew R Linford
The total ion current chromatogram (TICC) obtained by liquid-chromatography-mass spectrometry (LC-MS) is often extremely complex and 'noisy' in appearance, particularly when an electrospray ionization source is used. Accordingly, meaningful qualitative and quantitative information can be obtained in LC-MS by data mining processes. Here, one or more higher-quality mass chromatograms can be identified/extracted/isolated and combined to form a TICC, wherein much of the background mass noise is eliminated, and quantitative data for chromatographic peaks can be obtained...
April 21, 2018: Journal of Chromatography. A
https://www.readbyqxmd.com/read/29759240/reduced-graphene-oxide-zno-nanocomposite-based-electrochemical-sensor-for-sensitive-and-selective-monitoring-of-8-hydroxy-2-deoxyguanosine
#12
Junxing Hao, Kangbing Wu, Chidan Wan, Yong Tang
Developing reliable and feasible electrochemical sensors for the detection of 8-hydroxy-2'-deoxyguanosine (8-OHdG) is important because the urinary level of 8-OHdG is related to cancer disease. Moreover, the co-existed uric acid (UA) as an interference severe affects the sensitive detection of 8-OHdG. Herein, sensitive monitoring of 8-OHdG was conducted using a nanocomposite of reduced graphene oxide (rGO) and ZnO nanoparticles (ZnO@rGO) as the sensing material. This nanocomposite was prepared via in-situ reduction of GO with Zn powders...
August 1, 2018: Talanta
https://www.readbyqxmd.com/read/29757801/effects-of-additional-low-pass-filtered-speech-on-listening-effort-for-noise-band-vocoded-speech-in-quiet-and-in-noise
#13
Carina Pals, Anastasios Sarampalis, Mart van Dijk, Deniz Başkent
OBJECTIVES: Residual acoustic hearing in electric-acoustic stimulation (EAS) can benefit cochlear implant (CI) users in increased sound quality, speech intelligibility, and improved tolerance to noise. The goal of this study was to investigate whether the low-pass-filtered acoustic speech in simulated EAS can provide the additional benefit of reducing listening effort for the spectrotemporally degraded signal of noise-band-vocoded speech. DESIGN: Listening effort was investigated using a dual-task paradigm as a behavioral measure, and the NASA Task Load indeX as a subjective self-report measure...
May 11, 2018: Ear and Hearing
https://www.readbyqxmd.com/read/29757799/improved-detection-of-vowel-envelope-frequency-following-responses-using-hotelling-s-t2-analysis
#14
Frederique J Vanheusden, Steven L Bell, Michael A Chesnaye, David M Simpson
OBJECTIVES: Objective detection of brainstem responses to natural speech stimuli is an important tool for the evaluation of hearing aid fitting, especially in people who may not be able to respond reliably in behavioral tests. Of particular interest is the envelope frequency following response (eFFR), which refers to the EEG response at the stimulus' fundamental frequency (and its harmonics), and here in particular to the response to natural spoken vowel sounds. This article introduces the frequency-domain Hotelling's T (HT2) method for eFFR detection...
May 11, 2018: Ear and Hearing
https://www.readbyqxmd.com/read/29757231/speckle-filtering-of-gf-3-polarimetric-sar-data-with-joint-restriction-principle
#15
Jinwei Xie, Zhenfang Li, Chaowei Zhou, Yuyuan Fang, Qingjun Zhang
Polarimetric SAR (PolSAR) scattering characteristics of imagery are always obtained from the second order moments estimation of multi-polarization data, that is, the estimation of covariance or coherency matrices. Due to the extra-paths that signal reflected from separate scatterers within the resolution cell has to travel, speckle noise always exists in SAR images and has a severe impact on the scattering performance, especially on single look complex images. In order to achieve high accuracy in estimating covariance or coherency matrices, three aspects are taken into consideration: (1) the edges and texture of the scene are distinct after speckle filtering; (2) the statistical characteristic should be similar to the object pixel; and (3) the polarimetric scattering signature should be preserved, in addition to speckle reduction...
May 12, 2018: Sensors
https://www.readbyqxmd.com/read/29755848/ct-dose-modulation-using-automatic-exposure-control-in-whole-body-pet-ct-effects-of-scout-imaging-direction-and-arm-positioning
#16
Yusuke Inoue, Kazunori Nagahara, Hiroko Kudo, Hiroyasu Itoh
Automatic exposure control (AEC) modulates tube current and consequently X-ray exposure in CT. We investigated the behavior of AEC systems in whole-body PET/CT. CT images of a whole-body phantom were acquired using AEC on two scanners from different manufactures. The effects of scout imaging direction and arm positioning on dose modulation were evaluated. Image noise was assessed in the chest and upper abdomen. On one scanner, AEC using two scout images in the posteroanterior (PA) and lateral (Lat) directions provided relatively constant image noise along the z-axis with the arms at the sides...
2018: American Journal of Nuclear Medicine and Molecular Imaging
https://www.readbyqxmd.com/read/29750540/read-out-segmented-echo-planar-diffusion-imaging-of-the-female-pelvis-utility-in-endometrial-carcinoma-a-preliminary-experience
#17
Adarsh Ghosh, Tulika Singh, Veenu Singla, Rashmi Bagga, Radhika Srinivasan, Niranjan Khandelwal
OBJECTIVE: Susceptibility artefacts from bones and bowel, geometric distortion make diffusion imaging of the pelvis difficult. We discuss the difficulties of single-shot-echoplanar[ss-ep ]DWI and evaluate a new diffusion-weighted imaging technique - readout segmented echo planar[ rs-ep]DWI in endometrial carcinoma and discuss the imaging physics. METHODS: IRB approval was obtained and five consecutive patients underwent both rs-ep and ss-ep-DWI of the female pelvis and two radiologists compared the images...
May 11, 2018: British Journal of Radiology
https://www.readbyqxmd.com/read/29749048/evaluation-of-projection-and-dual-energy-based-methods-for-metal-artifact-reduction-in-ct-using-a-phantom-study
#18
Zaiyang Long, Michael R Bruesewitz, David R DeLone, Jonathan M Morris, Kimberly K Amrami, Mark C Adkins, Katrina N Glazebrook, James M Kofler, Shuai Leng, Cynthia H McCollough, Joel G Fletcher, Ahmed F Halaweish, Lifeng Yu
OBJECTIVES: Both projection and dual-energy (DE)-based methods have been used for metal artifact reduction (MAR) in CT. The two methods can also be combined. The purpose of this work was to evaluate these three MAR methods using phantom experiments for five types of metal implants. MATERIALS AND METHODS: Five phantoms representing spine, dental, hip, shoulder, and knee were constructed with metal implants. These phantoms were scanned using both single-energy (SE) and DE protocols with matched radiation output...
May 10, 2018: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/29746604/a-description-of-externally-recorded-womb-sounds-in-human-subjects-during-gestation
#19
Joanna J Parga, Robert Daland, Kalpashri Kesavan, Paul M Macey, Lonnie Zeltzer, Ronald M Harper
OBJECTIVE: Reducing environmental noise benefits premature infants in neonatal intensive care units (NICU), but excessive reduction may lead to sensory deprivation, compromising development. Instead of minimal noise levels, environments that mimic intrauterine soundscapes may facilitate infant development by providing a sound environment reflecting fetal life. This soundscape may support autonomic and emotional development in preterm infants. We aimed to assess the efficacy and feasibility of external non-invasive recordings in pregnant women, endeavoring to capture intra-abdominal or womb sounds during pregnancy with electronic stethoscopes and build a womb sound library to assess sound trends with gestational development...
2018: PloS One
https://www.readbyqxmd.com/read/29744731/factors-affecting-speech-reception-in-background-noise-with-a-vocoder-implementation-of-the-fast-algorithm
#20
Shaikat Hossain, Raymond L Goldsworthy
Speech segregation in background noise remains a difficult task for individuals with hearing loss. Several signal processing strategies have been developed to improve the efficacy of hearing assistive technologies in complex listening environments. The present study measured speech reception thresholds in normal-hearing listeners attending to a vocoder based on the Fundamental Asynchronous Stimulus Timing algorithm (FAST: Smith et al. 2014), which triggers pulses based on the amplitudes of channel magnitudes in order to preserve envelope timing cues, with two different reconstruction bandwidths (narrowband and broadband) to control the degree of spectrotemporal resolution...
May 9, 2018: Journal of the Association for Research in Otolaryngology: JARO
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