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Eisaku Oho, Kazuhiko Suzuki, Sadao Yamazaki
The current study describes a new support system for fine focusing and near-perfect astigmatism correction for scanning electron microscopy (SEM). The signal-to-noise ratio of a series of SEM images obtained from fast scan rates (TV scan) was adopted as a new metric for evaluating focus. Measured signal-to-noise ratio values were converted to an acoustic signal (sound wave frequency) using digital image processing techniques, enabling the SEM user to evaluate image focus using the auditory modality. Accurate focusing and correcting astigmatism in general-purpose SEM is traditionally time-consuming and difficult...
February 24, 2017: Microscopy
Kazuhiro Aoyama, Kotaro Nagano, Kaoru Mitsuoka
For three-dimensional analysis of cryo-specimens using tomography at low and medium magnifications, the use of STEM images has some important advantages over TEM. A clear understanding of the electron dose in STEM is essential for optimized cryo-microscopy so a dose estimation technique for STEM imaging has been developed. The STEM convergence angle was shown to have a large impact on the image quality, in particular on the signal-to-noise ratio in the acquired images. Importantly, there is a clear trade-off between good STEM spatial resolution in the images with a large convergence angle and the signal-to-noise ratio, which is improved by reducing the convergence angle as much as possible...
February 9, 2017: Microscopy
Patrick Trampert, Jonas Vogelgesang, Christian Schorr, Michael Maisl, Sviatoslav Bogachev, Nico Marniok, Alfred Louis, Tim Dahmen, Philipp Slusallek
BACKGROUND: Laminography is a tomographic technique that allows three-dimensional imaging of flat and elongated objects that stretch beyond the extent of a reconstruction volume. Laminography images can be reconstructed using iterative algorithms based on the Kaczmarz method. OBJECTIVE: This study aims to develop and demonstrate a new reconstruction algorithm that may provide superior image reconstruction quality for this challenged imaging application. METHODS: The images are initially represented using the coefficients over basis functions, which are typically piecewise constant functions (voxels)...
March 21, 2017: Journal of X-ray Science and Technology
Stefano Pirandola, Cosmo Lupo
We consider the estimation of noise parameters in a quantum channel, assuming the most general strategy allowed by quantum mechanics. This is based on the exploitation of unlimited entanglement and arbitrary quantum operations, so that the channel inputs may be interactively updated. In this general scenario, we draw a novel connection between quantum metrology and teleportation. In fact, for any teleportation-covariant channel (e.g., Pauli, erasure, or Gaussian channel), we find that adaptive noise estimation cannot beat the standard quantum limit, with the quantum Fisher information being determined by the channel's Choi matrix...
March 10, 2017: Physical Review Letters
J Goetz, S Pogorzalek, F Deppe, K G Fedorov, P Eder, M Fischer, F Wulschner, E Xie, A Marx, R Gross
In experiments with superconducting quantum circuits, characterizing the photon statistics of propagating microwave fields is a fundamental task. We quantify the n^{2}+n photon number variance of thermal microwave photons emitted from a blackbody radiator for mean photon numbers, 0.05≲n≲1.5. We probe the fields using either correlation measurements or a transmon qubit coupled to a microwave resonator. Our experiments provide a precise quantitative characterization of weak microwave states and information on the noise emitted by a Josephson parametric amplifier...
March 10, 2017: Physical Review Letters
Jukka I Väyrynen, Leonid I Glazman
We calculate the two-terminal current noise generated by a magnetic moment coupled to a helical edge of a two-dimensional topological insulator. When the system is symmetric with respect to in-plane spin rotation, the noise is dominated by the Nyquist component even in the presence of a voltage bias V. The corresponding noise spectrum S(V,ω) is determined by a modified fluctuation-dissipation theorem with the differential conductance G(V,ω) in place of the linear one. The differential noise ∂S/∂V, commonly measured in experiments, is strongly dependent on frequency on a small scale τ_{K}^{-1}≪T set by the Korringa relaxation rate of the local moment...
March 10, 2017: Physical Review Letters
C F Ockeloen-Korppi, E Damskägg, J-M Pirkkalainen, T T Heikkilä, F Massel, M A Sillanpää
A process which strongly amplifies both quadrature amplitudes of an oscillatory signal necessarily adds noise. Alternatively, if the information in one quadrature is lost in phase-sensitive amplification, it is possible to completely reconstruct the other quadrature. Here we demonstrate such a nearly perfect phase-sensitive measurement using a cavity optomechanical scheme, characterized by an extremely small noise less than 0.2 quanta. The device also strongly squeezes microwave radiation by 8 dB below vacuum...
March 10, 2017: Physical Review Letters
S Paesani, A A Gentile, R Santagati, J Wang, N Wiebe, D P Tew, J L O'Brien, M G Thompson
Quantum phase estimation is a fundamental subroutine in many quantum algorithms, including Shor's factorization algorithm and quantum simulation. However, so far results have cast doubt on its practicability for near-term, nonfault tolerant, quantum devices. Here we report experimental results demonstrating that this intuition need not be true. We implement a recently proposed adaptive Bayesian approach to quantum phase estimation and use it to simulate molecular energies on a silicon quantum photonic device...
March 10, 2017: Physical Review Letters
Jyh-Pin Chou, Alex Retzker, Adam Gali
The nitrogen-vacancy (NV) centre in diamond has shown great promise of nano-scale sensing applications, however, near-surface NV suer from relatively short spin coherence time that limits its sensitivity. This is presumably caused by improper surface termination. Using rst-principles calculations, we demonstrate that nitrogen terminated (111) diamond provides electrical inactivity and surface spin noise free properties. We also prove that the nitrogen terminated (111) surface can be fabricated by nitrogen plasma treatment...
March 24, 2017: Nano Letters
Ryan A Stevenson, Sarah H Baum, Magali Segers, Susanne Ferber, Morgan D Barense, Mark T Wallace
Speech perception in noisy environments is boosted when a listener can see the speaker's mouth and integrate the auditory and visual speech information. Autistic children have a diminished capacity to integrate sensory information across modalities, which contributes to core symptoms of autism, such as impairments in social communication. We investigated the abilities of autistic and typically-developing (TD) children to integrate auditory and visual speech stimuli in various signal-to-noise ratios (SNR). Measurements of both whole-word and phoneme recognition were recorded...
March 24, 2017: Autism Research: Official Journal of the International Society for Autism Research
Ikenna C Eze, Maria Foraster, Emmanuel Schaffner, Danielle Vienneau, Harris Héritier, Franziska Rudzik, Laurie Thiesse, Reto Pieren, Medea Imboden, Arnold von Eckardstein, Christian Schindler, Mark Brink, Christian Cajochen, Jean-Marc Wunderli, Martin Röösli, Nicole Probst-Hensch
Background: Epidemiological studies have inconsistently linked transportation noise and air pollution (AP) with diabetes risk. Most studies have considered single noise sources and/or AP, but none has investigated their mutually independent contributions to diabetes risk. Methods: We investigated 2631 participants of the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults (SAPALDIA), without diabetes in 2002 and without change of residence between 2002 and 2011...
March 13, 2017: International Journal of Epidemiology
Laurianne Cabrera, Lynne Werner
OBJECTIVES: Adults can use slow temporal envelope cues, or amplitude modulation (AM), to identify speech sounds in quiet. Faster AM cues and the temporal fine structure, or frequency modulation (FM), play a more important role in noise. This study assessed whether fast and slow temporal modulation cues play a similar role in infants' speech perception by comparing the ability of normal-hearing 3-month-olds and adults to use slow temporal envelope cues in discriminating consonants contrasts...
March 23, 2017: Ear and Hearing
Angelica I Aviles, Thomas Widlak, Alicia Casals, Maartje Nillesen, Habib Ammari
Cardiac motion estimation is an important diagnostic tool to detect heart diseases and it has been explored with modalities such as MRI and conventional ultrasound (US) sequences. US cardiac motion estimation still presents challenges because of the complex motion patterns and the presence of noise. In this work, we propose a novel approach to estimate the cardiac motion using ultrafast ultrasound data. -- Our solution is based on a variational formulation characterized by the L2-regularized class. The displacement is represented by a lattice of b-splines and we ensure robustness by applying a maximum likelihood type estimator...
March 24, 2017: Physics in Medicine and Biology
Saeed Ashrafinia, Hassan Mohy-Ud-Din, Nicolas Karakatsanis, Abhinav Jha, Michael Casey, Dan Kadrmas, Arman Rahmim
Point-Spread Function (PSF) modelling offers the capability to account for resolution degrading phenomena within the PET reconstruction framework. PSF modelling improves resolution and enhances contrast, but at the same time significantly alters image noise properties and induces edge overshoot effect. Thus, studying the effect of PSF modelling on quantitation task performance can be very important. Frameworks explored in the past involve a dichotomy of PSF vs. no-PSF modelling. By contrast, the present work focuses on quantitative performance evaluation of standard uptake value (SUV) PET images, while incorporating a wide spectrum of PSF models, including those that under- and over-estimate the true PSF, for the potential of enhanced quantitation of standardized uptake values (SUVs)...
March 24, 2017: Physics in Medicine and Biology
Chung-Jung Li, Tian Hong, Ying-Tsen Tung, Ya-Ping Yen, Ho-Chiang Hsu, Ya-Lin Lu, Mien Chang, Qing Nie, Jun-An Chen
The initial rostrocaudal patterning of the neural tube leads to differential expression of Hox genes that contribute to the specification of motor neuron (MN) subtype identity. Although several 3' Hox mRNAs are expressed in progenitors in a noisy manner, these Hox proteins are not expressed in the progenitors and only become detectable in postmitotic MNs. MicroRNA biogenesis impairment leads to precocious expression and propagates the noise of Hoxa5 at the protein level, resulting in an imprecise Hoxa5-Hoxc8 boundary...
March 24, 2017: Nature Communications
Qiqi Xu, Jianwen Zhao, Vincenzo Pecunia, Wenya Xu, Chunshan Zhou, Junyan Dou, Weibing Gu, Jian Lin, Lixin Mo, Yanfei Zhao, Zheng Cui
The fabrication of printed high-performance and environmentally stable n-type single-walled carbon nanotube (SWCNT) transistors and their integration into complementary (i.e. CMOS) circuits are widely recognized as key to achieving the full potential of carbon nanotube electronics. Here, we report a simple, efficient, and robust method to convert the polarity of SWCNT thin-film transistors (TFTs) using cheap and readily available ethanolamine as electron doping agent. Printed p-type bottom-gate SWCNT TFTs can be selectively converted into n-type by deposition of ethanolamine inks on the transistor active region via aerosol jet printing...
March 24, 2017: ACS Applied Materials & Interfaces
Chunmei Li, Zhilong Yu, Yusi Fu, Yuhong Pang, Yanyi Huang
We develop a novel single-cell-based platform through digital counting of amplified genomic DNA fragments, named multi-fraction amplification (mfA), to detect the copy number variations (CNVs) in a single cell. Amplification is required to acquire genomic information from a single cell, while introducing unavoidable bias. Unlike prevalent methods that directly infers CNV profiles from the pattern of sequencing depth, our mfA platform denatures and separates the DNA molecules from a single cell into multiple fractions of reaction mix before amplification...
March 24, 2017: ACS Applied Materials & Interfaces
X P Wang, B Wang, P Hou, R Li, J B Gao
We screened the suitable image reconstruction to observe the abdominal artery and compare the quality between the polychromatic and the monochromatic reconstruction images of the abdominal artery spectrum CT. Eighty patients underwent Gemstone CT energy spectrum imaging to obtain an abdominal artery polychromatic image (140 kVp) and a monochromatic image from 40 ~ 140 keV. The CT value of region of interest (ROI) was measured on the polychromatic image and the single energy image. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the abdominal aorta and hepatic artery were determined...
January 2017: Journal of Biological Regulators and Homeostatic Agents
S Notzon, N Vennewald, A Gajewska, A L Klahn, J Diemer, B Winter, I Fohrbeck, V Arolt, P Pauli, K Domschke, P Zwanzger
Previous studies suggest an inhibitory top-down control of the amygdala by the prefrontal cortex (PFC). Both brain regions play a role in the modulation of prepulse modification (PPM) of the acoustic startle response by a pre-stimulus. Repetitive transcranial magnetic stimulation (rTMS) can modulate the activity of the PFC and might thus affect PPM. This study tested the effect of inhibitory rTMS on PPM accounting for a genetic variant of the dopamine transporter gene (DAT1). Healthy participants (N = 102) were stimulated with continuous theta burst stimulation (cTBS, an intense form of inhibitory rTMS) or sham treatment over the right PFC...
March 24, 2017: European Archives of Psychiatry and Clinical Neuroscience
Mithila Durai, Grant D Searchfield
Objectives: A randomized cross-over trial in 18 participants tested the hypothesis that nature sounds, with unpredictable temporal characteristics and high valence would yield greater improvement in tinnitus than constant, emotionally neutral broadband noise. Study Design: The primary outcome measure was the Tinnitus Functional Index (TFI). Secondary measures were: loudness and annoyance ratings, loudness level matches, minimum masking levels, positive and negative emotionality, attention reaction and discrimination time, anxiety, depression and stress...
2017: Frontiers in Aging Neuroscience
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