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https://www.readbyqxmd.com/read/29777821/regional-cardiac-function-analysis-from-tagged-mri-images-comparison-of-techniques-harmonic-phase-harp-versus-sinusoidal-modeling-sinmod-analysis
#1
El-Sayed H Ibrahim, Jadranka Stojanovska, Azza Hassanein, Claire Duvernoy, Pierre Croisille, Rodica Pop-Busui, Scott D Swanson
Cardiac MRI tagging is a valuable technique for evaluating regional heart function. Currently, there are a number of different techniques for analyzing the tagged images. Specifically, k-space-based analysis techniques showed to be much faster than image-based techniques, where harmonic-phase (HARP) and sine-wave modeling (SinMod) stand as two famous techniques of the former group, which are frequently used in clinical studies. In this study, we compared HARP and SinMod and studied inter-observer variability between the two techniques for evaluating myocardial strain and apical-to-base torsion in numerical phantom, nine healthy controls, and thirty diabetic patients...
May 16, 2018: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/29718807/regulation-of-dynamic-postural-control-to-attend-manual-steadiness-constraints
#2
Luis Augusto Teixeira, Joane Figueiredo Serpa Coutinho, Daniel Boari Coelho
In daily living activities, performance of spatially accurate manual movements in upright stance depends on postural stability. In the present investigation, we aimed to evaluate the effect of the required manual steadiness (task constraint) on the regulation of dynamic postural control. A single group of young participants (n=20) were evaluated in the performance of a dual posturo-manual task of balancing on a platform oscillating in sinusoidal translations at 0.4 Hz (low) or 1 Hz (high) frequencies while stabilizing a cylinder on a handheld tray...
May 2, 2018: Journal of Neurophysiology
https://www.readbyqxmd.com/read/29666930/role-of-side-slip-flight-in-target-pursuit-blue-tailed-damselflies-ischnura-elegans-avoid-body-rotation-while-approaching-a-moving-perch
#3
Ziv Kassner, Gal Ribak
Visually guided flight control requires processing changes in the visual panorama (optic-flow) resulting from self-movement relative to stationary objects, as well as from moving objects passing through the field of view. We studied the ability of the blue-tailed damselfly, Ischnura elegans, to successfully land on a perch moving unpredictably. We tracked the insects landing on a vertical pole moved linearly 6 cm back and forth with sinusoidal changes in velocity. When the moving perch changed direction at frequencies higher than 1 Hz, the damselflies engaged in manoeuvres that typically involved sideways flight, with minimal changes in body orientation relative to the stationary environment...
April 17, 2018: Journal of Comparative Physiology. A, Neuroethology, Sensory, Neural, and Behavioral Physiology
https://www.readbyqxmd.com/read/29611210/interplay-effect-on-a-6-mv-flattening-filter-free-linear-accelerator-with-high-dose-rate-and-fast-multi-leaf-collimator-motion-treating-breast-and-lung-phantoms
#4
Tucker Netherton, Yuting Li, Paige Nitsch, Simona Shaitelman, Peter Balter, Song Gao, Ann Klopp, Manickam Muruganandham, Laurence Court
PURPOSE: Using a new linear accelerator with high dose rate (800 MU/min), fast MLC motions (5.0cm/s), fast gantry rotation (15sec/rotation), and 1cm wide MLCs, we aimed to quantify the effects of complexity, arc number, and fractionation on interplay for breast and lung treatments under target motion. METHODS: To study lung interplay, eight VMAT plans (one to six arcs) and four nine-field sliding-window IMRT plans varying in complexity were created. For the breast plans, four four-field sliding-window IMRT plans were created...
April 2, 2018: Medical Physics
https://www.readbyqxmd.com/read/29554010/the-effects-of-severe-myopia-on-the-properties-of-sampling-units-in-peripheral-retina
#5
Manbir Nagra, Bernard Gilmartin, Nicola S Logan, Stephen J Anderson
SIGNIFICANCE: Poor peripheral visual acuity in myopia may reflect, in part, photoreceptor misalignment with the exit pupil of the eye. We speculate that if such misalignment causes sufficient visual deprivation and/or disrupts retinal feedback processes, it may influence eye growth itself. PURPOSE: It is known that myopic eyes have a reduced peripheral resolution acuity relative to emmetropic eyes, though it remains unclear how mechanical stretching of the retina in myopia impacts on peripheral visual performance...
April 2018: Optometry and Vision Science: Official Publication of the American Academy of Optometry
https://www.readbyqxmd.com/read/29548071/three-bead-steering-microswimmers
#6
Mohd Suhail Rizvi, Alexander Farutin, Chaouqi Misbah
The self-propelled microswimmers have recently attracted considerable attention as model systems for biological cell migration as well as artificial micromachines. A simple and well-studied microswimmer model consists of three identical spherical beads joined by two springs in a linear fashion with active oscillatory forces being applied on the beads to generate self-propulsion. We have extended this linear microswimmer configuration to a triangular geometry where the three beads are connected by three identical springs in an equilateral triangular manner...
February 2018: Physical Review. E
https://www.readbyqxmd.com/read/29472086/image-quality-of-four-dimensional-cone-beam-computed-tomography-obtained-at-various-gantry-rotation-speeds-for-liver-stereotactic-body-radiation-therapy-with-fiducial-markers
#7
Yoshinobu Shimohigashi, Fujio Araki, Masato Maruyama, Keisuke Yonemura, Yuji Nakaguchi, Yudai Kai, Ryo Toya
In this study, qualities of 4D cone-beam CT (CBCT) images obtained using various gantry rotation speeds (GRSs) for liver stereotactic body radiation therapy (SBRT) with fiducial markers were quantitatively evaluated. Abdominal phantom containing a fiducial marker was moved along a sinusoidal waveform, and 4D-CBCT images were acquired with GRSs of 50-200° min-1 . We obtained the 4D-CBCT projection data from six patients who underwent liver SBRT and generated 4D-CBCT images at GRSs of 67-200° min-1 , by varying the number of projection data points...
January 2018: Physica Medica: PM
https://www.readbyqxmd.com/read/29385105/a-rotational-gyroscope-with-a-water-film-bearing-based-on-magnetic-self-restoring-effect
#8
Dianzhong Chen, Xiaowei Liu, Haifeng Zhang, Hai Li, Rui Weng, Ling Li, Wanting Rong, Zhongzhao Zhang
Stable rotor levitation is a challenge for rotational gyroscopes (magnetically suspended gyroscopes (MSG) and electrostatically suspended gyroscopes (ESG)) with a ring- or disk-shaped rotor, which restricts further improvement of gyroscope performance. In addition, complicated pick-up circuits and feedback control electronics propose high requirement on fabrication technology. In the proposed gyroscope, a ball-disk shaped rotor is supported by a water-film bearing, formed by centrifugal force to deionized water at the cavity of the lower supporting pillar...
January 31, 2018: Sensors
https://www.readbyqxmd.com/read/29304173/the-reliability-of-nonlinear-least-squares-algorithm-for-data-analysis-of-neural-response-activity-during-sinusoidal-rotational-stimulation-in-semicircular-canal-neurons
#9
Pengyu Ren, Bowen Li, Shiyao Dong, Lin Chen, Yuelin Zhang
Although many mathematical methods were used to analyze the neural activity under sinusoidal stimulation within linear response range in vestibular system, the reliabilities of these methods are still not reported, especially in nonlinear response range. Here we chose nonlinear least-squares algorithm (NLSA) with sinusoidal model to analyze the neural response of semicircular canal neurons (SCNs) during sinusoidal rotational stimulation (SRS) over a nonlinear response range. Our aim was to acquire a reliable mathematical method for data analysis under SRS in vestibular system...
2018: PloS One
https://www.readbyqxmd.com/read/29289032/phase-synchronization-of-baroclinic-waves-in-a-differentially-heated-rotating-annulus-experiment-subject-to-periodic-forcing-with-a-variable-duty-cycle
#10
P L Read, X Morice-Atkinson, E J Allen, A A Castrejón-Pita
A series of laboratory experiments in a thermally driven, rotating fluid annulus are presented that investigate the onset and characteristics of phase synchronization and frequency entrainment between the intrinsic, chaotic, oscillatory amplitude modulation of travelling baroclinic waves and a periodic modulation of the (axisymmetric) thermal boundary conditions, subject to time-dependent coupling. The time-dependence is in the form of a prescribed duty cycle in which the periodic forcing of the boundary conditions is applied for only a fraction δ of each oscillation...
December 2017: Chaos
https://www.readbyqxmd.com/read/29170018/ocular-torsion-responses-to-sinusoidal-electrical-vestibular-stimulation
#11
Stuart W Mackenzie, Raymond F Reynolds
BACKGROUND: Eye movements evoked by electrical vestibular stimulation (EVS) offer potential for diagnosing vestibular dysfunction. However, ocular recording techniques are often too invasive or impractical for routine clinical use. Furthermore, the kinematic nature of the EVS signal is not fully understood in terms of movement sensations. NEW METHOD: We apply sinusoidal EVS stimuli varying from 0.05 to 20Hz, and record the eye in darkness using an infrared camera...
January 15, 2018: Journal of Neuroscience Methods
https://www.readbyqxmd.com/read/29155009/thresholds-for-sine-wave-corrugations-defined-by-binocular-disparity-in-random-dot-stereograms-factor-analysis-of-individual-differences-revealstwo-stereoscopic-mechanisms-tuned-for-spatial-frequency
#12
David H Peterzell, Ignacio Serrano-Pedraza, Michael Widdall, Jenny C A Read
Threshold functions for sinusoidal depth corrugations typically reach their minimum (highest sensitivity) at spatial frequencies of 0.2-0.4 cycles/degree (cpd), with lower thresholds for horizontal than vertical corrugations at low spatial frequencies. To elucidate spatial frequency and orientation tuning of stereoscopic mechanisms, we measured the disparity sensitivity functions, and used factor analytic techniques to estimate the existence of independent underlying stereo channels. The data set (N=30 individuals) was for horizontal and vertical corrugations of spatial frequencies ranging from 0...
November 15, 2017: Vision Research
https://www.readbyqxmd.com/read/29130902/dielectrophoresis-based-multi-step-nanowire-assembly-on-a-flexible-superstrate
#13
Xin Wang, Ke Chen, Linbo Liu, Nan Xiang, Zhonghua Ni
Nanowire assembly based on dielectrophoresis (DEP) could be a useful and efficient tool for fabricating nanowire-based devices. Although there have been extensive reports on the DEP nanowire assembly, the new approaches that make DEP more facile and affordable are still desirable. Herein, we present an approach using the reusable electrodes to assemble silver nanowires onto a removable, independent polyethylene terephthalate (PET) film. The PET film is placed on the reusable electrodes, and a sinusoidal AC voltage is applied to the electrodes to induce DEP force for nanowire assembly upon the flexible film...
January 12, 2018: Nanotechnology
https://www.readbyqxmd.com/read/29096123/in-vitro-validation-of-a-novel-mechanical-model-for-testing-the-anchorage-capacity-of-pedicle-screws-using-physiological-load-application
#14
Christian Liebsch, Julia Zimmermann, Nicolas Graf, Christoph Schilling, Hans-Joachim Wilke, Annette Kienle
Biomechanical in vitro tests analysing screw loosening often include high standard deviations caused by high variabilities in bone mineral density and pedicle geometry, whereas standardized mechanical models made of PU foam often do not integrate anatomical or physiological boundary conditions. The purpose of this study was to develop a most realistic mechanical model for the standardized and reproducible testing of pedicle screws regarding the resistance against screw loosening and the holding force as well as to validate this model by in vitro experiments...
October 25, 2017: Journal of the Mechanical Behavior of Biomedical Materials
https://www.readbyqxmd.com/read/29081426/bilateral-vestibulopathy-diagnostic-criteria-consensus-document-of-the-classification-committee-of-the-b%C3%A3-r%C3%A3-ny-society
#15
Michael Strupp, Ji-Soo Kim, Toshihisa Murofushi, Dominik Straumann, Joanna C Jen, Sally M Rosengren, Charles C Della Santina, Herman Kingma
This paper describes the diagnostic criteria for bilateral vestibulopathy (BVP) by the Classification Committee of the Bárány Society. The diagnosis of BVP is based on the patient history, bedside examination and laboratory evaluation. Bilateral vestibulopathy is a chronic vestibular syndrome which is characterized by unsteadiness when walking or standing, which worsen in darkness and/or on uneven ground, or during head motion. Additionally, patients may describe head or body movement-induced blurred vision or oscillopsia...
2017: Journal of Vestibular Research: Equilibrium & Orientation
https://www.readbyqxmd.com/read/29070026/a-biomechanical-comparison-of-kirschner-wire-fixation-on-fracture-stability-in-salter-harris-type-i-fractures-of-the-proximal-humeral-physis-in-a-porcine-cadaveric-model
#16
Jiawen Ma, Tian Wang, Vedran Lovric, Kenneth A Johnson, William R Walsh
BACKGROUND: The physis is the weakest component of immature long bones, and physeal fractures constitute about 30% of fractures in growing dogs. Fractures of the proximal humeral physis typically have a Salter Harris type I or II configuration. These fractures require accurate reduction and adequate stabilization to allow for any potential continued longitudinal bone growth, in conjunction with physeal fracture healing. Conventional internal fixation of these fractures involves insertion of two parallel Kirschner wires, although other methods described include tension band wiring, Rush pinning, and lag screws...
October 25, 2017: BMC Veterinary Research
https://www.readbyqxmd.com/read/29051726/head-stabilization-in-the-pigeon-role-of-vision-to-correct-for-translational-and-rotational-disturbances
#17
Leslie M Theunissen, Nikolaus F Troje
Stabilization of the head in animals with limited capacity to move their eyes is key to maintain a stable image on the retina. In many birds, including pigeons, a prominent example for the important role of head stabilization is the characteristic head-bobbing behavior observed during walking. Multimodal sensory feedback from the eyes, the vestibular system and proprioceptors in body and neck is required to control head stabilization. Here, we trained unrestrained pigeons ( Columba livia ) to stand on a perch that was sinusoidally moved with a motion platform along all three translational and three rotational degrees of freedom...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/29041614/fast-two-snapshot-structured-illumination-for-temporal-focusing-microscopy-with-enhanced-axial-resolution
#18
Yunlong Meng, Wei Lin, Chenglin Li, Shih-Chi Chen
We present a new two-snapshot structured light illumination (SLI) reconstruction algorithm for fast image acquisition. The new algorithm, which only requires two mutually π phase-shifted raw structured images, is implemented on a custom-built temporal focusing fluorescence microscope (TFFM) to enhance its axial resolution via a digital micromirror device (DMD). First, the orientation of the modulated sinusoidal fringe patterns is automatically identified via spatial frequency vector detection. Subsequently, the modulated in-focal-plane images are obtained via rotation and subtraction...
September 18, 2017: Optics Express
https://www.readbyqxmd.com/read/28984802/vestibular-function-change-in-a-vasopressin-induced-hydrops-model
#19
Minbum Kim, Kyu-Sung Kim
HYPOTHESIS: A vasopressin-induced endoymphatic hydrops model can represent an acute vertiginous attack in Menière's disease (MD). BACKGROUND: Previous animal models are not appropriate to evaluate the efficacy of new treatments for hydrops because they cannot represent an acute attack of MD. Recently, a new dynamic model was introduced for acute hydrops exacerbation using the vasopressin type 2 receptor agonist, desmopressin (1-deamino-8-D-Arginine vasopressin, VP); however, resulting changes in vestibular function have not been investigated...
December 2017: Otology & Neurotology
https://www.readbyqxmd.com/read/28945777/effects-of-head-tilt-on-visual-field-testing-with-a-head-mounted-perimeter-imo
#20
Sayaka Yamao, Chota Matsumoto, Hiroki Nomoto, Takuya Numata, Mariko Eura, Marika Yamashita, Shigeki Hashimoto, Sachiko Okuyama, Shinji Kimura, Kenzo Yamanaka, Yasutaka Chiba, Makoto Aihara, Yoshikazu Shimomura
PURPOSE: A newly developed head-mounted perimeter termed "imo" enables visual field (VF) testing without a fixed head position. Because the positional relationship between the subject's head and the imo is fixed, the effects of head position changes on the test results are small compared with those obtained using a stationary perimeter. However, only ocular counter-roll (OCR) induced by head tilt might affect VF testing. To quantitatively reveal the effects of head tilt and OCR on the VF test results, we investigated the associations among the head-tilt angle, OCR amplitude and VF testing results...
2017: PloS One
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