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https://www.readbyqxmd.com/read/27911297/sample-size-estimation-for-alzheimer-s-disease-trials-from-japanese-adni-serial-magnetic-resonance-imaging
#1
Motonobu Fujishima, Atsushi Kawaguchi, Norihide Maikusa, Ryozo Kuwano, Takeshi Iwatsubo, Hiroshi Matsuda
BACKGROUND: Little is known about the sample sizes required for clinical trials of Alzheimer's disease (AD)-modifying treatments using atrophy measures from serial brain magnetic resonance imaging (MRI) in the Japanese population. OBJECTIVE: The primary objective of the present study was to estimate how large a sample size would be needed for future clinical trials for AD-modifying treatments in Japan using atrophy measures of the brain as a surrogate biomarker...
November 28, 2016: Journal of Alzheimer's Disease: JAD
https://www.readbyqxmd.com/read/27911291/a-metal-free-method-for-producing-mri-contrast-at-amyloid-%C3%AE
#2
Silvia Hilt, Tang Tang, Jeffrey H Walton, Madhu Budamagunta, Izumi Maezawa, Tamás Kálai, Kálmán Hideg, Vikrant Singh, Heike Wulff, Qizhi Gong, Lee-Way Jin, Angelique Louie, John C Voss
Alzheimer's disease (AD) is characterized by depositions of the amyloid-β (Aβ) peptide in the brain. The disease process develops over decades, with substantial neurological loss occurring before a clinical diagnosis of dementia can be rendered. It is therefore imperative to develop methods that permit early detection and monitoring of disease progression. In addition, the multifactorial pathogenesis of AD has identified several potential avenues for AD intervention. Thus, evaluation of therapeutic candidates over lengthy trial periods also demands a practical, noninvasive method for measuring Aβ in the brain...
November 26, 2016: Journal of Alzheimer's Disease: JAD
https://www.readbyqxmd.com/read/27910916/measuring-the-coefficient-of-friction-of-a-small-floating-liquid-marble
#3
Chin Hong Ooi, Anh Van Nguyen, Geoffrey M Evans, Dzung Viet Dao, Nam-Trung Nguyen
This paper investigates the friction coefficient of a moving liquid marble, a small liquid droplet coated with hydrophobic powder and floating on another liquid surface. A floating marble can easily move across water surface due to the low friction, allowing for the transport of aqueous solutions with minimal energy input. However, the motion of a floating marble has yet to be systematically characterised due to the lack of insight into key parameters such as the coefficient of friction between the floating marble and the carrier liquid...
December 2, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27910663/multi-energy-sxr-cameras-for-magnetically-confined-fusion-plasmas-invited
#4
L F Delgado-Aparicio, J Maddox, N Pablant, K Hill, M Bitter, J E Rice, R Granetz, A Hubbard, J Irby, M Greenwald, E Marmar, K Tritz, D Stutman, B Stratton, P Efthimion
A compact multi-energy soft x-ray camera has been developed for time, energy and space-resolved measurements of the soft-x-ray emissivity in magnetically confined fusion plasmas. Multi-energy soft x-ray imaging provides a unique opportunity for measuring, simultaneously, a variety of important plasma properties (Te, nZ, ΔZeff, and ne,fast). The electron temperature can be obtained by modeling the slope of the continuum radiation from ratios of the available brightness and inverted radial emissivity profiles over multiple energy ranges...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910650/full-wave-feasibility-study-of-anti-radar-diagnostic-of-magnetic-field-based-on-o-x-mode-conversion-and-oblique-reflectometry-imaging
#5
Orso Meneghini, Francesco A Volpe
An innovative millimeter wave diagnostic is proposed to measure the local magnetic field and edge current as a function of the minor radius in the tokamak pedestal region. The idea is to identify the direction of minimum reflectivity at the O-mode cutoff layer. Correspondingly, the transmissivity due to O-X mode conversion is maximum. That direction, and the angular map of reflectivity around it, contains information on the magnetic field vector B at the cutoff layer. Probing the plasma with different wave frequencies provides the radial profile of B...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910585/the-eddy-current-probe-array-for-keda-torus-experiment
#6
Zichao Li, Hong Li, Cui Tu, Jintong Hu, Wei You, Bing Luo, Mingsheng Tan, Yolbarsop Adil, Yanqi Wu, Biao Shen, Bingjia Xiao, Ping Zhang, Wenzhe Mao, Hai Wang, Xiaohui Wen, Haiyang Zhou, Jinlin Xie, Tao Lan, Adi Liu, Weixing Ding, Chijin Xiao, Wandong Liu
In a reversed field pinch device, the conductive shell is placed as close as possible to the plasma so as to balance the plasma during discharge. Plasma instabilities such as the resistive wall mode and certain tearing modes, which restrain the plasma high parameter operation, respond closely with conditions in the wall, in essence the eddy current present. Also, the effect of eddy currents induced by the external coils cannot be ignored when active control is applied to control instabilities. One diagnostic tool, an eddy current probe array, detects the eddy current in the composite shell...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910529/development-of-a-beam-ion-velocity-detector-for-the-heavy-ion-beam-probe
#7
P J Fimognari, T P Crowley, D R Demers
In an axisymmetric plasma, the conservation of canonical angular momentum constrains heavy ion beam probe (HIBP) trajectories such that measurement of the toroidal velocity component of secondary ions provides a localized determination of the poloidal flux at the volume where they originated. We have developed a prototype detector which is designed to determine the beam angle in one dimension through the detection of ion current landing on two parallel planes of detecting elements. A set of apertures creates a pattern of ion current on wires in the first plane and solid metal plates behind them; the relative amounts detected by the wires and plates determine the angle which beam ions enter the detector, which is used to infer the toroidal velocity component...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910511/diamagnetic-measurements-based-on-the-compensation-of-tf-current-diffusion-in-j-text
#8
L Z Zhu, Z P Chen, F M Li, H Liu, Z Y Chen, G Zhuang
Due to the existence both of toroidal ripples and toroidal field (TF) current diffusion, the toroidal flux changes with time when the TF current is at the flat-top. A diamagnetic measurement based on the compensation of TF current diffusion has been built in J-TEXT to solve this problem. The measurement system includes a double-loop installed in the vacuum vessel and an array of small printed circuit board (PCB) magnetic probes placed on the mid-plane of one TF coil. A model was proposed to analyze and compensate the effect of TF current diffusion...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910427/a-temporally-and-spatially-resolved-electron-density-diagnostic-method-for-the-edge-plasma-based-on-stark-broadening
#9
A Zafar, E H Martin, S C Shannon, R C Isler, J B O Caughman
An electron density diagnostic (≥10(10) cm(-3)) capable of high temporal (ms) and spatial (mm) resolution is currently under development at Oak Ridge National Laboratory. The diagnostic is based on measuring the Stark broadened, Doppler-free spectral line profile of the n = 6-2 hydrogen Balmer series transition. The profile is then fit to a fully quantum mechanical model including the appropriate electric and magnetic field operators. The quasi-static approach used to calculate the Doppler-free spectral line profile is outlined here and the results from the model are presented for H-δ spectra for electron densities of 10(10)-10(13) cm(-3)...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910411/design-and-characterization-of-a-prototype-divertor-viewing-infrared-video-bolometer-for-nstx-u
#10
G G van Eden, M L Reinke, B J Peterson, T K Gray, L F Delgado-Aparicio, M A Jaworski, J Lore, K Mukai, R Sano, S N Pandya, T W Morgan
The InfraRed Video Bolometer (IRVB) is a powerful tool to measure radiated power in magnetically confined plasmas due to its ability to obtain 2D images of plasma emission using a technique that is compatible with the fusion nuclear environment. A prototype IRVB has been developed and installed on NSTX-U to view the lower divertor. The IRVB is a pinhole camera which images radiation from the plasma onto a 2.5 μm thick, 9 × 7 cm(2) Pt foil and monitors the resulting spatio-temporal temperature evolution using an IR camera...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910404/using-a-priori-knowledge-for-developing-bolometric-tomography-in-toroidal-devices
#11
Ryuichi Sano, Byron J Peterson, Kiyofumi Mukai, Masaru Teranishi, Naofumi Iwama, Masahiro Kobayashi
In tomographic imaging of magnetically confined toroidal plasmas, a countermeasure against missing observation has been studied in terms of the adoption of prior information based on modelled plasma profiles. The Tikhonov regularization for image reconstruction is extended by the use of the Euclidean distance. A procedure of model fitting is designed in order to adaptively generate the reference image. The new method is tested on a typical example of ill-conditioned tomography, that is, the three-dimensional imaging-bolometer tomography in the large helical device...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910396/four-dimensional-4d-tracking-of-high-temperature-microparticles
#12
Zhehui Wang, Q Liu, W Waganaar, J Fontanese, D James, T Munsat
High-speed tracking of hot and molten microparticles in motion provides rich information about burning plasmas in magnetic fusion. An exploding-wire apparatus is used to produce moving high-temperature metallic microparticles and to develop four-dimensional (4D) or time-resolved 3D particle tracking techniques. The pinhole camera model and algorithms developed for computer vision are used for scene calibration and 4D reconstructions. 3D positions and velocities are then derived for different microparticles...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910386/spatial-and-temporal-analysis-of-diii-d-3d-magnetic-diagnostic-data
#13
E J Strait, J D King, J M Hanson, N C Logan
An extensive set of magnetic diagnostics in DIII-D is aimed at measuring non-axisymmetric "3D" features of tokamak plasmas, with typical amplitudes ∼10(-3) to 10(-5) of the total magnetic field. We describe hardware and software techniques used at DIII-D to condition the individual signals and analysis to estimate the spatial structure from an ensemble of discrete measurements. Applications of the analysis include detection of non-rotating MHD instabilities, plasma control, and validation of MHD stability and 3D equilibrium models...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910373/development-of-a-spectroscopic-technique-for-simultaneous-magnetic-field-electron-density-and-temperature-measurements-in-icf-relevant-plasmas
#14
E C Dutra, J A Koch, R Presura, W A Angermeier, T Darling, S Haque, R C Mancini, A M Covington
Spectroscopic techniques in the visible range are often used in plasma experiments to measure B-field induced Zeeman splitting, electron densities via Stark broadening, and temperatures from Doppler broadening. However, when electron densities and temperatures are sufficiently high, the broadening of the Stark and Doppler components can dominate the emission spectra and obscure the Zeeman component. In this research, we are developing a time-resolved multi-axial technique for measuring the Zeeman, Stark, and Doppler broadened line emission of dense magnetized plasmas for Z-pinch and Dense Plasma Focus (DPF) accelerators...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910366/the-rectangular-array-of-magnetic-probes-on-j-text-tokamak
#15
Zhipeng Chen, Fuming Li, Ge Zhuang, Xiang Jian, Lizhi Zhu
The rectangular array of magnetic probes system was newly designed and installed in the torus on J-TEXT tokamak to measure the local magnetic fields outside the last closed flux surface at a single toroidal angle. In the implementation, the experimental results agree well with the theoretical results based on the Spool model and three-dimensional numerical finite element model when the vertical field was applied. Furthermore, the measurements were successfully used as the input of EFIT code to conduct the plasma equilibrium reconstruction...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910074/evolutional-characterization-of-photochemically-induced-stroke-in-rats-a-multimodality-imaging-and-molecular-biological-study
#16
Nai-Wei Liu, Chien-Chih Ke, Yonghua Zhao, Yi-An Chen, Kim-Chuan Chan, David Tat-Wei Tan, Jhih-Shian Lee, You-Yin Chen, Tun-Wei Hsu, Ya-Ju Hsieh, Chi-Wei Chang, Bang-Hung Yang, Wen-Sheng Huang, Ren-Shyan Liu
Photochemically induced cerebral ischemia is an easy-manipulated, reproducible, relatively noninvasive, and lesion controllable model for translational study of ischemic stroke. In order to longitudinally investigate the characterization of the model, magnetic resonance imaging, (18)F-2-deoxy-glucose positron emission tomography, fluorescence, and bioluminescence imaging system were performed in correlation with triphenyl tetrazolium chloride (TTC), hematoxylin-eosin staining, and immunohistochemistry examinations of glial fibrillary acidic protein, CD68, NeuN, von willebrand factor, and α-smooth muscle actin in the infarct zone...
December 1, 2016: Translational Stroke Research
https://www.readbyqxmd.com/read/27909683/fronto-striatal-glutamate-in-children-with-tourette-s-disorder-and-attention-deficit-hyperactivity-disorder
#17
Jilly Naaijen, Natalie J Forde, David J Lythgoe, Sophie E A Akkermans, Thaira J C Openneer, Andrea Dietrich, Marcel P Zwiers, Pieter J Hoekstra, Jan K Buitelaar
OBJECTIVE: Both Tourette's disorder (TD) and attention-deficit/hyperactivity disorder (ADHD) have been related to abnormalities in glutamatergic neurochemistry in the fronto-striatal circuitry. TD and ADHD often co-occur and the neural underpinnings of this co-occurrence have been insufficiently investigated in prior studies. METHOD: We used proton magnetic resonance spectroscopy (1H-MRS) in children between 8 and 12 years of age (TD n = 15, ADHD n = 39, TD + ADHD n = 29, and healthy controls n = 53) as an in vivo method of evaluating glutamate concentrations in the fronto-striatal circuit...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/27909413/sex-effects-on-smoking-cue-perception-in-non-smokers-smokers-and-ex-smokers-a-pilot-study
#18
Davide Zanchi, Arthur Brody, Stefan Borgwardt, Sven Haller
INTRODUCTION: Recent neuroimaging research suggests sex-related brain differences in smoking addiction. In the present pilot study, we assessed gender-related differences in brain activation in response to cigarette-related video cues, investigating non-smokers, smokers, and ex-smokers. METHODS: First, we compared 29 females (28.6 ± 5.3) vs. 23 males (31.5 ± 6.4), regardless of current smoking status to assess global gender-related effects. Second, we performed a post hoc analysis of non-smokers (9 females and 8 males), smokers (10 females and 8 males), and ex-smokers (10 females and 7 males)...
2016: Frontiers in Psychiatry
https://www.readbyqxmd.com/read/27909144/bone-area-provides-a-responsive-outcome-measure-for-bone-changes-in-short-term-knee-osteoarthritis-studies
#19
Michael A Bowes, Rose A Maciewicz, John C Waterton, David J Hunter, Philip G Conaghan
OBJECTIVE: To analyze the 3-D bone area from an osteoarthritis (OA) cohort demonstrating no change in cartilage thickness. METHODS: Twenty-seven women with painful medial knee OA had magnetic resonance images at 0, 3, and 6 months. Images were analyzed using active appearance models. RESULTS: At 3 and 6 months, the mean change in medial femoral bone area was 0.34% (95% CI 0.04-0.64) and 0.61% (95% CI 0.32-0.90), respectively. Forty-one percent of the subjects had progression greater than the smallest detectable difference at 6 months...
December 2016: Journal of Rheumatology
https://www.readbyqxmd.com/read/27909099/neural-tuning-to-numerosity-relates-to-perceptual-tuning-in-3-to-6-year-old-children
#20
Alyssa J Kersey, Jessica F Cantlon
: Neural representations of approximate numerical value, or numerosity, have been observed in the intraparietal sulcus (IPS) in monkeys and humans, including children. Using functional magnetic resonance imaging (fMRI) we show that children as young as 3 to 4 years old exhibit neural tuning to cardinal numerosities in the IPS and that their neural responses are accounted for by a model of numerosity coding that has been used to explain neural responses in the adult IPS. We also found that the sensitivity of children's neural tuning to number in the right IPS was comparable to their numerical discrimination sensitivity observed behaviorally, outside of the scanner...
December 1, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
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