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https://www.readbyqxmd.com/read/28930492/time-trends-in-concussion-symptom-presentation-and-assessment-methods-in-high-school-athletes
#1
Dustin W Currie, Matthew J Kraeutler, John B Schrock, Eric C McCarty, R Dawn Comstock
BACKGROUND: Concussion rates have increased significantly over the past decade. This may reflect an increase in the knowledge and diagnosis of the symptoms of a concussion rather than a true increase in the incidence. Assessing trends in the way that concussions are presenting to and being identified by clinicians over the same period may provide additional insight into the apparent rise in concussions. PURPOSE: To evaluate patterns of change in concussion symptom presentation, diagnostic/evaluation methods, and symptom resolution time reported for United States high school athletes from the 2007-2008 through 2014-2015 academic years...
September 1, 2017: American Journal of Sports Medicine
https://www.readbyqxmd.com/read/28922116/iterative-low-dose-ct-reconstruction-with-priors-trained-by-artificial-neural-network
#2
Dufan Wu, Kyungsang Kim, Georges El Fakhri, Quanzheng Li
Dose reduction in computed tomography (CT) is essential for decreasing radiation risk in clinical applications. Iterative reconstruction algorithms are one of the most promising way to compensate for the increased noise due to reduction of photon flux. Most iterative reconstruction algorithms incorporate manually designed prior functions of the reconstructed image to suppress noises while maintaining structures of the image. These priors basically rely on smoothness constraints and cannot exploit more complex features of the image...
September 15, 2017: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28918981/potential-impacts-of-shipping-noise-on-marine-mammals-in-the-western-canadian-arctic
#3
William D Halliday, Stephen J Insley, R Casey Hilliard, Tyler de Jong, Matthew K Pine
As the Arctic warms and sea ice decreases, increased shipping will lead to higher ambient noise levels in the Arctic Ocean. Arctic marine mammals are vulnerable to increased noise because they use sound to survive and likely evolved in a relatively quiet soundscape. We model vessel noise propagation in the proposed western Canadian Arctic shipping corridor in order to examine impacts on marine mammals and marine protected areas (MPAs). Our model predicts that loud vessels are audible underwater when >100km away, could affect marine mammal behaviour when within 2km for icebreakers vessels, and as far as 52km for tankers...
September 15, 2017: Marine Pollution Bulletin
https://www.readbyqxmd.com/read/28918597/effect-of-vibration-on-postural-control-and-gait-of-elderly-subjects-a-systematic-review
#4
REVIEW
Atefeh Aboutorabi, Mokhtar Arazpour, Mahmood Bahramizadeh, Farzam Farahmand, Reza Fadayevatan
BACKGROUND AND AIM: Gait and balance disorders are common in the elderly populations, and their prevalence increases with age. This systematic review was performed to summarize the current evidence for subthreshold vibration interventions on postural control and gait in elderly. METHOD: A review of intervention studies including the following words in the title/abstract: insole, foot and ankle appliances, vibration, noise and elderly related to balance and gait...
September 16, 2017: Aging Clinical and Experimental Research
https://www.readbyqxmd.com/read/28914807/development-optimization-and-in-vitro-in-vivo-characterization-of-collagen-dextran-spongious-wound-dressings-loaded-with-flufenamic-acid
#5
Mihaela Violeta Ghica, Mădălina Georgiana Albu Kaya, Cristina-Elena Dinu-Pîrvu, Dumitru Lupuleasa, Denisa Ioana Udeanu
The aim of this study was the development and optimization of some topical collagen-dextran sponges with flufenamic acid, designed to be potential dressings for burn wounds healing. The sponges were obtained by lyophilization of hydrogels based on type I fibrillar collagen gel extracted from calf hide, dextran and flufenamic acid, crosslinked and un-crosslinked, and designed according to a 3-factor, 3-level Box-Behnken experimental design. The sponges showed good fluid uptake ability quantified by a high swelling ratio...
September 15, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28906567/self-calibrating-wave-encoded-variable-density-single-shot-fast-spin-echo-imaging
#6
Feiyu Chen, Valentina Taviani, Jonathan I Tamir, Joseph Y Cheng, Tao Zhang, Qiong Song, Brian A Hargreaves, John M Pauly, Shreyas S Vasanawala
BACKGROUND: It is highly desirable in clinical abdominal MR scans to accelerate single-shot fast spin echo (SSFSE) imaging and reduce blurring due to T2 decay and partial-Fourier acquisition. PURPOSE: To develop and investigate the clinical feasibility of wave-encoded variable-density SSFSE imaging for improved image quality and scan time reduction. STUDY TYPE: Prospective controlled clinical trial. SUBJECTS: With Institutional Review Board approval and informed consent, the proposed method was assessed on 20 consecutive adult patients (10 male, 10 female, range, 24-84 years)...
September 14, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28906241/tracking-of-noise-tolerance-to-measure-hearing-aid-benefit
#7
Francis Kuk, Eric Seper, Chi-Chuen Lau, Petri Korhonen
BACKGROUND: The benefits offered by noise reduction (NR) features on a hearing aid had been studied traditionally using test conditions that set the hearing aids into a stable state of performance. While adequate, this approach does not allow the differentiation of two NR algorithms that differ in their timing characteristics (i.e., activation and stabilization time). PURPOSE: The current study investigated a new method of measuring noise tolerance (Tracking of Noise Tolerance [TNT]) as a means to differentiate hearing aid technologies...
September 2017: Journal of the American Academy of Audiology
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
#8
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/28901621/objective-comparison-of-high-contrast-spatial-resolution-and-low-contrast-detectability-for-various-clinical-protocols-on-multiple-ct-scanners
#9
Damien Racine, Anaïs Viry, Fabio Becce, Sabine Schmidt, Alexandre Ba, François O Bochud, Sue Edyvean, Alexander Schegerer, Francis R Verdun
PURPOSE: We sought to compare objectively computed tomography (CT) scanner performance for three clinically relevant protocols using a task-based image quality assessment method in order to assess the potential for radiation dose reduction. METHODS: Four CT scanners released between 2003 and 2007 by different manufacturers were compared with four CT scanners released between 2012 and 2014 by the same manufacturers using ideal linear model observers (MO): prewhitening (PW) MO and channelized Hotelling (CHO) MO with Laguerre-Gauss channels for high-contrast spatial resolution and low-contrast detectability (LCD) performance, respectively...
September 2017: Medical Physics
https://www.readbyqxmd.com/read/28901618/technical-note-a-model-based-sinogram-correction-for-beam-hardening-artifact-reduction-in-ct
#10
Sung Min Lee, Jin Keun Seo, Yong Eun Chung, Jongduk Baek, Hyoung Suk Park
PURPOSE: This study aims to propose a physics-based method of reducing beam-hardening artifacts induced by high-attenuation materials such as metal stents or other metallic implants. METHODS: The proposed approach consists of deriving a sinogram inconsistency formula representing the energy dependence of the attenuation coefficient of high-attenuation materials. This inconsistency formula more accurately represents the inconsistencies of the sinogram than that of a previously reported formula (called the MAC-BC method)...
September 2017: Medical Physics
https://www.readbyqxmd.com/read/28901610/low-dose-dynamic-myocardial-perfusion-ct-imaging-using-a-motion-adaptive-sparsity-prior
#11
Zhaoying Bian, Dong Zeng, Zhang Zhang, Changfei Gong, Xiumei Tian, Gang Yan, Jing Huang, Hong Guo, Bo Chen, Jing Zhang, Qianjin Feng, Wufan Chen, Jianhua Ma
PURPOSE: Dynamic myocardial perfusion computed tomography (DM-PCT) imaging offers benefits over quantitative assessment of myocardial blood flow (MBF) for diagnosis and risk stratification of coronary artery disease. However, one major drawback of DM-PCT imaging is that a high radiation level is imparted by repeated scanning. To address this issue, in this work, we developed a statistical iterative reconstruction algorithm based on the penalized weighted least-squares (PWLS) scheme by incorporating a motion adaptive sparsity prior (MASP) model to achieve high-quality DM-PCT imaging with low tube current dynamic data acquisition...
September 2017: Medical Physics
https://www.readbyqxmd.com/read/28901609/adaptive-non-local-means-on-local-principle-neighborhood-for-noise-artifacts-reduction-in-low-dose-ct-images
#12
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/28901607/bias-variance-tradeoff-in-anticorrelated-noise-reduction-for-spectral-ct
#13
Mats Persson, Fredrik Grönberg
PURPOSE: In spectral CT, basis material decomposition is commonly used to generate a set of basis images showing the material composition at each point in the field of view. The noise in these images typically contains anticorrelations between the different basis images, which leads to increased noise in each basis image. These anticorrelations can be removed by changing the basis functions used in the material decomposition, but the resulting basis images can then no longer be used for quantitative measurements...
September 2017: Medical Physics
https://www.readbyqxmd.com/read/28900202/pixelated-checkerboard-metasurface-for-ultra-wideband-radar-cross-section-reduction
#14
Mohammad-Javad Haji-Ahmadi, Vahid Nayyeri, Mohammad Soleimani, Omar M Ramahi
In this paper we designed and fabricated a metasurface working as a radar cross section (RCS) reducer over an ultra wide band of frequency from 3.8 to 10.7 GHz. The designed metasurface is a chessboard-like surface made of alternating tiles, with each tile composed of identical unit cells. We develop a novel, simple, highly robust and fully automated approach for designing the unit cells. First, a topology optimization algorithm is used to engineer the shape of the two unit cells. The area of each unit cell is pixelated...
September 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28894831/assessment-and-improvement-of-sound-quality-in-cochlear-implant-users
#15
REVIEW
Meredith T Caldwell, Nicole T Jiam, Charles J Limb
OBJECTIVES: Cochlear implants (CIs) have successfully provided speech perception to individuals with sensorineural hearing loss. Recent research has focused on more challenging acoustic stimuli such as music and voice emotion. The purpose of this review is to evaluate and describe sound quality in CI users with the purposes of summarizing novel findings and crucial information about how CI users experience complex sounds. DATA SOURCES: Here we review the existing literature on PubMed and Scopus to present what is known about perceptual sound quality in CI users, discuss existing measures of sound quality, explore how sound quality may be effectively studied, and examine potential strategies of improving sound quality in the CI population...
June 2017: Laryngoscope Investigative Otolaryngology
https://www.readbyqxmd.com/read/28889780/prevalence-of-hearing-loss-and-associated-factors-in-subjects-with-normal-otoscopy-a-national-cross-sectional-study
#16
Hong Ju Park, Myung Hoon Yoo, Sook-Young Woo, Seon Woo Kim, Yang-Sun Cho
OBJECTIVE: To report the prevalence of hearing loss (HL) and associated factors in a nationwide study. DESIGN: Cross-sectional study. STUDY SAMPLE: We investigated the prevalence of HL in 10,845 participants ≥12 years of age and analysed the associated factors with HL from 7434 participants ≥40 years of age. RESULTS: The prevalence of worse ear HL was 21.9% (1.2% in youngest and 81.9% in oldest) and that of better ear was 12...
September 11, 2017: International Journal of Audiology
https://www.readbyqxmd.com/read/28887836/a-novel-method-for-quantification-of-beam-s-eye-view-tumor-tracking-performance
#17
Yue-Houng Hu, Marios Myronakis, Joerg Rottmann, Adam Wang, Daniel Morf, Daniel Shedlock, Paul Baturin, Josh Star-Lack, Ross Berbeco
PURPOSE: In-treatment imaging using an electronic portal imaging device (EPID) can be used to confirm patient and tumor positioning. Real-time tumor tracking performance using current digital megavolt (MV) imagers is hindered by poor image quality. Novel EPID designs may help to improve quantum noise response, while also preserving the high spatial resolution of the current clinical detector. Recently investigated EPID design improvements include but are not limited to multi-layer imager (MLI) architecture, thick crystalline and amorphous scintillators, and phosphor pixilation and focusing...
September 9, 2017: Medical Physics
https://www.readbyqxmd.com/read/28881235/mri-compatibility-study-of-an-integrated-pet-rf-coil-prototype-system-at-3t
#18
Md Shahadat Hossain Akram, Takayuki Obata, Mikio Suga, Fumihiko Nishikido, Eiji Yoshida, Kazuyuki Saito, Taiga Yamaya
We have been working on the development of a PET insert for existing magnetic resonance imaging (MRI) systems for simultaneous PET/MR imaging, which integrates radiofrequency (RF)-shielded PET detector modules with an RF head coil. In order to avoid interferences between the PET detector circuits and the different MRI-generated electromagnetic fields, PET detector circuits were installed inside eight Cu-shielded fiber-reinforced plastic boxes, and these eight shielded PET modules were integrated in between the eight elements of a 270-mm-diameter and 280-mm-axial-length cylindrical birdcage RF coil, which was designed to be used with a 3-T clinical MRI system...
August 31, 2017: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/28881037/comparison-of-vessel-enhancement-algorithms-applied-to-time-of-flight-mra-images-for-cerebrovascular-segmentation
#19
Renzo Phellan, Nils D Forkert
PURPOSE: Vessel enhancement algorithms are often used as a preprocessing step for vessel segmentation in medical images to improve the overall segmentation accuracy. Each algorithm uses different characteristics to enhance vessels, such that the most suitable algorithm may vary for different applications. This paper presents a comparative analysis of the accuracy gains in vessel segmentation generated by the use of nine vessel enhancement algorithms: Multiscale vesselness using the formulas described by Erdt (MSE), Frangi (MSF), and Sato (MSS), optimally oriented ux (OOF), ranking orientations responses path operator (RORPO), the regularized Perona-Malik approach (RPM), vessel enhanced diffusion (VED), hybrid diffusion with continuous switch (HDCS), and the white top hat algorithm (WTH)...
September 7, 2017: Medical Physics
https://www.readbyqxmd.com/read/28880284/direct-instrumental-identification-of-catalytically-active-surface-sites
#20
Jonas H K Pfisterer, Yunchang Liang, Oliver Schneider, Aliaksandr S Bandarenka
The activity of heterogeneous catalysts-which are involved in some 80 per cent of processes in the chemical and energy industries-is determined by the electronic structure of specific surface sites that offer optimal binding of reaction intermediates. Directly identifying and monitoring these sites during a reaction should therefore provide insight that might aid the targeted development of heterogeneous catalysts and electrocatalysts (those that participate in electrochemical reactions) for practical applications...
September 6, 2017: Nature
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