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https://www.readbyqxmd.com/read/28107743/high-sensitivity-four-layer-polymer-fiber-optic-evanescent-wave-sensor
#1
Xin Xin, Nianbing Zhong, Qiang Liao, Yanyan Cen, Ruohua Wu, Zhengkun Wang
We present a novel four-layer structure consisting of bottom, second, third, and surface layers in the sensing region, for a D-shaped step-index fiber-optic evanescent wave (FOEW) sensor. To reduce the background noise, the surface of the longitudinal section in the D-shaped region is coated with a light-absorbing film. We check the morphologies of the second and surface layers, examine the refractive indices (RIs) of the third and surface layers, and analyze the composition of the surface layer. We also investigate the effects of the thicknesses and RIs of the third and surface layers and the LA film on the light transmission and sensitivity of the FOEW sensors...
January 11, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28107025/least-squares-moving-window-spectral-analysis
#2
Young Jong Lee
Least squares regression is proposed as a moving-windows method for analysis of a series of spectra acquired as a function of external perturbation. The least squares moving-window (LSMW) method can be considered an extended form of the Savitzky-Golay differentiation for nonuniform perturbation spacing. LSMW is characterized in terms of moving-window size, perturbation spacing type, and intensity noise. Simulation results from LSMW are compared with results from other numerical differentiation methods, such as single-interval differentiation, autocorrelation moving-window, and perturbation correlation moving-window methods...
January 1, 2017: Applied Spectroscopy
https://www.readbyqxmd.com/read/28106936/whole-brain-vessel-wall-mri-a-parameter-tune-up-solution-to-improve-the-scan-efficiency-of-three-dimensional-variable-flip-angle-turbo-spin-echo
#3
Qi Yang, Zixin Deng, Xiaoming Bi, Shlee S Song, Konrad H Schlick, Nestor R Gonzalez, Debiao Li, Zhaoyang Fan
PURPOSE: To propose and evaluate a parameter tune-up solution to expedite a three-dimensional (3D) variable-flip-angle turbo spin-echo (TSE) sequence for whole-brain intracranial vessel wall (IVW) imaging. MATERIALS AND METHODS: Elliptical k-space sampling and prolonged echo train length (ETL), were used to expedite a 3D variable-flip-angle TSE-based sequence. To compensate for the potential loss in vessel wall signal, optimal combination of prescribed T2 and ETL was experimentally investigated on 22 healthy volunteers at 3 Tesla...
January 20, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28106840/a-low-complexity-method-for-two-dimensional-direction-of-arrival-estimation-using-an-l-shaped-array
#4
Qing Wang, Hang Yang, Hua Chen, Yangyang Dong, Laihua Wang
In this paper, a new low-complexity method for two-dimensional (2D) direction-of-arrival (DOA) estimation is proposed. Based on a cross-correlation matrix formed from the L-shaped array, the proposed algorithm obtains the automatic pairing elevation and azimuth angles without eigendecomposition, which can avoid high computational cost. In addition, the cross-correlation matrix eliminates the effect of noise, which can achieve better DOA performance. Then, the theoretical error of the algorithm is analyzed and the Cramer-Rao bound (CRB) for the direction of arrival estimation is derived ...
January 19, 2017: Sensors
https://www.readbyqxmd.com/read/28106825/snr-and-standard-deviation-of-cgnss-r-and-ignss-r-scatterometric-measurements
#5
Alberto Alonso-Arroyo, Jorge Querol, Carlos Lopez-Martinez, Valery U Zavorotny, Hyuk Park, Daniel Pascual, Raul Onrubia, Adriano Camps
This work addresses the accuracy of the Global Navigation Satellite Systems (GNSS)-Reflectometry (GNSS-R) scatterometric measurements considering the presence of both coherent and incoherent scattered components, for both conventional GNSS-R (cGNSS-R) and interferometric GNSS-R (iGNSS-R) techniques. The coherent component is present for some type of surfaces, and it has been neglected until now because it vanishes for the sea surface scattering case. Taking into account the presence of both scattering components, the estimated Signal-to-Noise Ratio (SNR) for both techniques is computed based on the detectability criterion, as it is done in conventional GNSS applications...
January 19, 2017: Sensors
https://www.readbyqxmd.com/read/28106746/fisheye-based-method-for-gps-localization-improvement-in-unknown-semi-obstructed-areas
#6
Julien Moreau, Sébastien Ambellouis, Yassine Ruichek
A precise GNSS (Global Navigation Satellite System) localization is vital for autonomous road vehicles, especially in cluttered or urban environments where satellites are occluded, preventing accurate positioning. We propose to fuse GPS (Global Positioning System) data with fisheye stereovision to face this problem independently to additional data, possibly outdated, unavailable, and needing correlation with reality. Our stereoscope is sky-facing with 360° × 180° fisheye cameras to observe surrounding obstacles...
January 17, 2017: Sensors
https://www.readbyqxmd.com/read/28106718/an-improved-high-sensitivity-airborne-transient-electromagnetic-sensor-for-deep-penetration
#7
Shudong Chen, Shuxu Guo, Haofeng Wang, Miao He, Xiaoyan Liu, Yu Qiu, Shuang Zhang, Zhiwen Yuan, Haiyang Zhang, Dong Fang, Jun Zhu
The investigation depth of transient electromagnetic sensors can be effectively increased by reducing the system noise, which is mainly composed of sensor internal noise, electromagnetic interference (EMI), and environmental noise, etc. A high-sensitivity airborne transient electromagnetic (AEM) sensor with low sensor internal noise and good shielding effectiveness is of great importance for deep penetration. In this article, the design and optimization of such an AEM sensor is described in detail. To reduce sensor internal noise, a noise model with both a damping resistor and a preamplifier is established and analyzed...
January 17, 2017: Sensors
https://www.readbyqxmd.com/read/28106615/metal-artifact-reduction-in-x-ray-computed-tomography-using-computer-aided-design-data-of-implants-as-prior-information
#8
Veikko Ruth, Daniel Kolditz, Christian Steiding, Willi A Kalender
OBJECTIVES: The performance of metal artifact reduction (MAR) methods in x-ray computed tomography (CT) suffers from incorrect identification of metallic implants in the artifact-affected volumetric images. The aim of this study was to investigate potential improvements of state-of-the-art MAR methods by using prior information on geometry and material of the implant. MATERIALS AND METHODS: The influence of a novel prior knowledge-based segmentation (PS) compared with threshold-based segmentation (TS) on 2 MAR methods (linear interpolation [LI] and normalized-MAR [NORMAR]) was investigated...
January 18, 2017: Investigative Radiology
https://www.readbyqxmd.com/read/28106453/giant-amplification-of-noise-in-fluctuation-induced-pattern-formation
#9
Tommaso Biancalani, Farshid Jafarpour, Nigel Goldenfeld
The amplitude of fluctuation-induced patterns might be expected to be proportional to the strength of the driving noise, suggesting that such patterns would be difficult to observe in nature. Here, we show that a large class of spatially extended dynamical systems driven by intrinsic noise can exhibit giant amplification, yielding patterns whose amplitude is comparable to that of deterministic Turing instabilities. The giant amplification results from the interplay between noise and nonorthogonal eigenvectors of the linear stability matrix, yielding transients that grow with time, and which, when driven by the ever-present intrinsic noise, lead to persistent large amplitude patterns...
January 6, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28106279/a-rapid-electrochemical-monitoring-platform-for-sensitive-determination-of-thiamethoxam-based-on-%C3%AE-cyclodextrin-graphene-composite
#10
XingChen Zhai, Hua Zhang, Min Zhang, Xin Yang, Cheng Gu, GuoPeng Zhou, Haitian Zhao, Zhenyu Wang, Aijun Dong, Jing Wang
A rapid monitoring platform for sensitive voltammetric detection of thiamethoxam (TMX) residues was reported in the present study. The β-cyclodextrin-reduced graphene oxide composite (β-CD-rGO) was used as a reinforcing material in electrochemical determination of TMX. Compared with bare glassy carbon electrode (GCE), the reduction peak currents of TMX at rGO/GCE and β-CD-rGO/GCE were increased by 70 and 124 folds, respectively. The experimental conditions influencing voltammetric determination of TMX, such as the amount of β-CD-rGO, solution pH, temperature and time on accumulation, were optimized...
January 20, 2017: Environmental Toxicology and Chemistry
https://www.readbyqxmd.com/read/28106132/m-otdr-sensing-system-based-on-3d-encoded-microstructures
#11
Qizhen Sun, Fan Ai, Deming Liu, Jianwei Cheng, Hongbo Luo, Kuan Peng, Yiyang Luo, Zhijun Yan, Perry Ping Shum
In this work, a quasi-distributed sensing scheme named as microstructured OTDR (M-OTDR) by introducing ultra-weak microstructures along the fiber is proposed. Owing to its relative higher reflectivity compared with the backscattered coefficient in fiber and three dimensional (3D) i.e. wavelength/frequency/time encoded property, the M-OTDR system exhibits the superiorities of high signal to noise ratio (SNR), high spatial resolution of millimeter level and high multiplexing capacity up to several ten thousands theoretically...
January 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28106129/retooling-laser-speckle-contrast-analysis-algorithm-to-enhance-non-invasive-high-resolution-laser-speckle-functional-imaging-of-cutaneous-microcirculation
#12
Surya C Gnyawali, Kevin Blum, Durba Pal, Subhadip Ghatak, Savita Khanna, Sashwati Roy, Chandan K Sen
Cutaneous microvasculopathy complicates wound healing. Functional assessment of gated individual dermal microvessels is therefore of outstanding interest. Functional performance of laser speckle contrast imaging (LSCI) systems is compromised by motion artefacts. To address such weakness, post-processing of stacked images is reported. We report the first post-processing of binary raw data from a high-resolution LSCI camera. Sharp images of low-flowing microvessels were enabled by introducing inverse variance in conjunction with speckle contrast in Matlab-based program code...
January 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28105915/spectral-consensus-strategy-for-accurate-reconstruction-of-large-biological-networks
#13
Séverine Affeldt, Nataliya Sokolovska, Edi Prifti, Jean-Daniel Zucker
BACKGROUND: The last decades witnessed an explosion of large-scale biological datasets whose analyses require the continuous development of innovative algorithms. Many of these high-dimensional datasets are related to large biological networks with few or no experimentally proven interactions. A striking example lies in the recent gut bacterial studies that provided researchers with a plethora of information sources. Despite a deeper knowledge of microbiome composition, inferring bacterial interactions remains a critical step that encounters significant issues, due in particular to high-dimensional settings, unknown gut bacterial taxa and unavoidable noise in sparse datasets...
December 13, 2016: BMC Bioinformatics
https://www.readbyqxmd.com/read/28105890/multitasking-during-degraded-speech-recognition-in-school-age-children
#14
Tina M Grieco-Calub, Kristina M Ward, Laurel Brehm
Multitasking requires individuals to allocate their cognitive resources across different tasks. The purpose of the current study was to assess school-age children's multitasking abilities during degraded speech recognition. Children (8 to 12 years old) completed a dual-task paradigm including a sentence recognition (primary) task containing speech that was either unprocessed or noise-band vocoded with 8, 6, or 4 spectral channels and a visual monitoring (secondary) task. Children's accuracy and reaction time on the visual monitoring task was quantified during the dual-task paradigm in each condition of the primary task and compared with single-task performance...
January 2017: Trends in Hearing
https://www.readbyqxmd.com/read/28105830/improving-performance-metrics-of-ultraviolet-photodissociation-mass-spectrometry-by-selective-precursor-ejection
#15
Dustin D Holden, Jennifer S Brodbelt
Confident protein identifications derived from high-throughput bottom-up and top-down proteomics workflows depend on acquisition of thousands of tandem mass spectrometry (MS/MS) spectra with adequate signal-to-noise and accurate mass assignments of the fragment ions. Ultraviolet photodissociation (UVPD) using 193 nm photons has proven to be well-suited for activation and fragmentation of peptides and proteins in ion trap mass spectrometers, but the spectral signal-to-noise ratio (S/N) is typically lower than that obtained from collisional activation methods...
January 3, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28105469/qin-dawg-validation-of-gradient-nonlinearity-bias-correction-workflow-for-quantitative-diffusion-weighted-imaging-in-multicenter-trials
#16
Dariya I Malyarenko, Lisa J Wilmes, Lori R Arlinghaus, Michael A Jacobs, Wei Huang, Karl G Helmer, Bachir Taouli, Thomas E Yankeelov, David Newitt, Thomas L Chenevert
Previous research has shown that system-dependent gradient nonlinearity (GNL) introduces a significant spatial bias (nonuniformity) in apparent diffusion coefficient (ADC) maps. Here, the feasibility of centralized retrospective system-specific correction of GNL bias for quantitative diffusion-weighted imaging (DWI) in multisite clinical trials is demonstrated across diverse scanners independent of the scanned object. Using corrector maps generated from system characterization by ice-water phantom measurement completed in the previous project phase, GNL bias correction was performed for test ADC measurements from an independent DWI phantom (room temperature agar) at two offset locations in the bore...
December 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28104643/reduced-patient-radiation-exposure-during-neurodiagnostic-and-interventional-x-ray-angiography-with-a-new-imaging-platform
#17
K van der Marel, S Vedantham, I M J van der Bom, M Howk, T Narain, K Ty, A Karellas, M J Gounis, A S Puri, A K Wakhloo
BACKGROUND AND PURPOSE: Advancements in medical device and imaging technology as well as accruing clinical evidence have accelerated the growth of the endovascular treatment of cerebrovascular diseases. However, the augmented role of these procedures raises concerns about the radiation dose to patients and operators. We evaluated patient doses from an x-ray imaging platform with radiation dose-reduction technology, which combined image noise reduction, motion correction, and contrast-dependent temporal averaging with optimized x-ray exposure settings...
January 19, 2017: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/28104237/one-step-green-synthesis-of-%C3%AE-cyclodextrin-iron-oxide-reduced-graphene-oxide-nanocomposite-with-high-supramolecular-recognition-capability-application-for-vortex-assisted-magnetic-solid-phase-extraction-of-organochlorine-pesticides-residue-from-honey-samples
#18
Shokouh Mahpishanian, Hassan Sereshti
In this research, β-cyclodextrin/iron oxide reduced graphene oxide hybrid nanostructure (β-CD/MRGO) with high water dispersability, excellent magnetic responsivity and molecular selectivity was prepared via a facile one step green strategy. The obtained nanomaterial was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, and vibrating sample magnetometry (VSM), which confirmed the modification of GO with β-CD and magnetic nanoparticles...
January 14, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28103803/variational-inference-for-rare-variant-detection-in-deep-heterogeneous-next-generation-sequencing-data
#19
Fan Zhang, Patrick Flaherty
BACKGROUND: The detection of rare single nucleotide variants (SNVs) is important for understanding genetic heterogeneity using next-generation sequencing (NGS) data. Various computational algorithms have been proposed to detect variants at the single nucleotide level in mixed samples. Yet, the noise inherent in the biological processes involved in NGS technology necessitates the development of statistically accurate methods to identify true rare variants. RESULTS: We propose a Bayesian statistical model and a variational expectation maximization (EM) algorithm to estimate non-reference allele frequency (NRAF) and identify SNVs in heterogeneous cell populations...
January 19, 2017: BMC Bioinformatics
https://www.readbyqxmd.com/read/28103789/nonlinear-dimensionality-reduction-methods-for-synthetic-biology-biobricks-visualization
#20
Jiaoyun Yang, Haipeng Wang, Huitong Ding, Ning An, Gil Alterovitz
BACKGROUND: Visualizing data by dimensionality reduction is an important strategy in Bioinformatics, which could help to discover hidden data properties and detect data quality issues, e.g. data noise, inappropriately labeled data, etc. As crowdsourcing-based synthetic biology databases face similar data quality issues, we propose to visualize biobricks to tackle them. However, existing dimensionality reduction methods could not be directly applied on biobricks datasets. Hereby, we use normalized edit distance to enhance dimensionality reduction methods, including Isomap and Laplacian Eigenmaps...
January 19, 2017: BMC Bioinformatics
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