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wave reflection

Izumi Matsuda, Izumi Matsudaaa
Recent studies have shown that a memorized item in the Concealed Information Test elicits a frontal negative slow wave (500-1000 ms) of the event-related potential, the cortical source of which involves the right prefrontal cortex. To examine whether this negative slow wave reflects a process that is specific to concealment rather than a more general cognitive control process, we compared the event-related potentials of 24 participants in four conditions involving the presence or absence of memory and the intention to conceal...
April 17, 2018: Biological Psychology
Kyo-Tae Kim, Joo-Hee Kim, Ye-Ji Heo, Cheol-Ha Baek, Si-Cheol Noh, Yun-Seon Choi, Ki-Jung Ahn, Heung-Lae Cho, Chi-Woong Mun, Sung-Kwang Park
With increasingly strict regulations regarding patient exposure, research on digital radiography technology has recently focused on indirect methods that can produce high-quality images for a low radiation dose. In particular, medical imaging systems based on indirect methods universally use rare-earth metal phosphors, because of their high atomic number and excellent luminescence efficiency. Thus, various studies aiming to improve the luminescence efficiency of phosphors have been conducted. Despite this research, however, the current luminescence efficiencies are insufficient...
September 1, 2018: Journal of Nanoscience and Nanotechnology
Thomas Pauwelyn, Richard Stahl, Lakyn Mayo, Xuan Zheng, Andy Lambrechts, Stefan Janssens, Liesbet Lagae, Veerle Reumers, Dries Braeken
The high rate of drug attrition caused by cardiotoxicity is a major challenge for drug development. Here, we developed a reflective lens-free imaging (RLFI) approach to non-invasively record in vitro cell deformation in cardiac monolayers with high temporal (169 fps) and non-reconstructed spatial resolution (352 µm) over a field-of-view of maximally 57 mm2 . The method is compatible with opaque surfaces and silicon-based devices. Further, we demonstrated that the system can detect the impairment of both contractility and fast excitation waves in cardiac monolayers...
April 1, 2018: Biomedical Optics Express
Xuejun Zhang, Ze Wu, Fu Liu, Qiangqiang Fu, Xiaoyong Chen, Jian Xu, Zhaochuan Zhang, Yunyun Huang, Yong Tang, Tuan Guo, Jacques Albert
We propose and demonstrate hydrogen peroxide (H2 O2 ) and glucose concentration measurements using a plasmonic optical fiber sensor. The sensor utilizes a tilted fiber Bragg grating (TFBG) written in standard single mode communication fiber. The fiber is over coated with an nm-scale film of silver that supports surface plasmon resonances (SPRs). Such a tilted grating SPR structure provides a high density of narrow spectral resonances (Q-factor about 105 ) that overlap with the broader absorption band of the surface plasmon waves in the silver film, thereby providing an accurate tool to measure small shifts of the plasmon resonance frequencies...
April 1, 2018: Biomedical Optics Express
Faith J Scott, Erika L Sesti, Eric J Choi, Alexander J Laut, Jagadishwar R Sirigiri, Alexander B Barnes
We introduce a novel design for millimeter wave electromagnetic structures within magic angle spinning (MAS) rotors. In this demonstration, a copper coating is vacuum deposited onto the outside surface of a sapphire rotor at a thickness of 50 nanometers. This thickness is sufficient to reflect 197 GHz microwaves, yet not too thick as to interfere with radiofrequency fields at 300 MHz or prevent sample spinning due to eddy currents. Electromagnetic simulations of an idealized rotor geometry show a microwave quality factor of 148...
April 19, 2018: Magnetic Resonance in Chemistry: MRC
Adolf M Sandbichler, Bianca Jansen, Bettina A Peer, Monika Paulitsch, Bernd Pelster, Margit Egg
BACKGROUND/AIMS: Reduced oxygen availability, hypoxia, is frequently encountered by organisms, tissues and cells, in aquatic environments as well as in high altitude or under pathological conditions such as infarct, stroke or cancer. The hypoxic signaling pathway was found to be mutually intertwined with circadian timekeeping in vertebrates and, as reported recently, also in mammals. However, the impact of hypoxia on intracellular metabolic oscillations is still unknown. METHODS: For determination of metabolites we used Multilabel Reader based fluorescence and luminescence assays, circadian levels of Hypoxia Inducible Factor 1 alpha and oxidized peroxiredoxins were semi quantified by Western blotting and ratiometric quantification of cytosolic and mitochondrial H2O2 was achieved with stable transfections of a redox sensitive green fluorescent protein sensor into zebrafish fibroblasts...
April 16, 2018: Cellular Physiology and Biochemistry
Jia Ji Yang, Yong Zhi Cheng, Chen Chen Ge, Rong Zhou Gong
A class of linear polarization conversion coding metasurfaces (MSs) based on a metal cut-wire structure is proposed, which can be applied to the reduction properties of radar cross section (RCS). We firstly present a hypothesis based on the principle of planar array theory, and then verify the RCS reduction characteristics using linear polarization conversion coding MSs by simulations and experiments. The simulated results show that in the frequency range of 6⁻14 GHz, the linear polarization conversion ratio reaches a maximum value of 90%, which is in good agreement with the theoretical predictions...
April 19, 2018: Materials
Ali Momeni, Kasra Rouhi, Hamid Rajabalipanah, Ali Abdolali
Inspired by the information theory, a new concept of re-programmable encrypted graphene-based coding metasurfaces was investigated at terahertz frequencies. A channel-coding function was proposed to convolutionally record an arbitrary information message onto unrecognizable but recoverable parity beams generated by a phase-encrypted coding metasurface. A single graphene-based reflective cell with dual-mode biasing voltages was designed to act as "0" and "1" meta-atoms, providing broadband opposite reflection phases...
April 18, 2018: Scientific Reports
Aviv D Mizrahi-Kliger, Alexander Kaplan, Zvi Israel, Hagai Bergman
Slow oscillations of neuronal activity alternating between firing and silence are a hallmark of slow-wave sleep (SWS). These oscillations reflect the default activity present in all mammalian species, and are ubiquitous to anesthesia, brain slice preparations, and neuronal cultures. In all these cases, neuronal firing is highly synchronous within local circuits, suggesting that oscillation-synchronization coupling may be a governing principle of sleep physiology regardless of anatomical connectivity. To investigate whether this principle applies to overall brain organization, we recorded the activity of individual neurons from basal ganglia (BG) structures and the thalamocortical (TC) network over 70 full nights of natural sleep in two vervet monkeys...
April 16, 2018: Proceedings of the National Academy of Sciences of the United States of America
Anna B Catino, Rebecca A Hubbard, Julio A Chirinos, Ray Townsend, Stephen Keefe, Naomi B Haas, Igor Puzanov, James C Fang, Neeraj Agarwal, David Hyman, Amanda M Smith, Mary Gordon, Theodore Plappert, Virginia Englefield, Vivek Narayan, Steven Ewer, Chantal ElAmm, Daniel Lenihan, Bonnie Ky
BACKGROUND: Sunitinib, used widely in metastatic renal cell carcinoma, can result in hypertension, left ventricular dysfunction, and heart failure. However, the relationships between vascular function and cardiac dysfunction with sunitinib are poorly understood. METHODS AND RESULTS: In a multicenter prospective study of 84 metastatic renal cell carcinoma patients, echocardiography, arterial tonometry, and BNP (B-type natriuretic peptide) measures were performed at baseline and at 3...
March 2018: Circulation. Heart Failure
J Steinlechner
Gravitational waves are detected by measuring length changes between mirrors in the arms of kilometre-long Michelson interferometers. Brownian thermal noise arising from thermal vibrations of the mirrors can limit the sensitivity to distance changes between the mirrors, and, therefore, the ability to measure gravitational-wave signals. Thermal noise arising from the highly reflective mirror coatings will limit the sensitivity both of current detectors (when they reach design performance) and of planned future detectors...
May 28, 2018: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
Kai Wang, Menglong Liu, Zhongqing Su, Shenfang Yuan, Zheng Fan
To characterize fatigue cracks, in the undersized stage in particular, preferably in a quantitative and precise manner, a two-dimensional (2D) analytical model is developed for interpreting the modulation mechanism of a "breathing" crack on guided ultrasonic waves (GUWs). In conjunction with a modal decomposition method and a variational principle-based algorithm, the model is capable of analytically depicting the propagating and evanescent waves induced owing to the interaction of probing GUWs with a "breathing" crack, and further extracting linear and nonlinear wave features (e...
March 17, 2018: Ultrasonics
Pierre Nauleau, Iason Zacharias Apostolakis, Matthew McGarry, Elisa E Konofagou
The stiffness of the arteries is known to be an indicator of the progression of various cardiovascular diseases. Clinically, the pulse wave velocity (PWV) is used as a surrogate for the arterial stiffness. Pulse Wave Imaging (PWI) is a non-invasive, ultrasound-based imaging technique capable of mapping the motion of the vessel walls allowing local assessment of the arterial properties. Conventionally, a distinctive feature of the displacement wave (e.g. the 50% upstroke) is tracked across the map to estimate the PWV...
April 16, 2018: Physics in Medicine and Biology
Hongchao Xie, Shengwei Jiang, Jie Shan, Kin Fai Mak
We demonstrate robust optical bistability, the phenomenon of two well-discriminated stable states depending upon the history of the optical input, in fully suspended monolayers of WSe2 at low temperatures near the exciton resonance. Optical bistability has been achieved under continuous-wave optical excitation that is red-detuned from the exciton resonance at an intensity level of 103 W/cm2. The observed bistability is originated from a photo-thermal mechanism, which provides both optical nonlinearity and passive feedback, which are the two essential elements for optical bistability...
April 16, 2018: Nano Letters
S V Revenko, L N Tikhomirova, A V Nesterov, I A Tarakanov
In experiments on narcotized rats, BP in the left femoral artery as well as local electrical potential and electrical impedance of the symmetric segment of the right femoral artery were simultaneously recorded in situ with two extracellular nonpolarizable Ag/AgCl electrodes located along the artery at a distance of 3 mm from each other. The pulsatile arterial electrical potentials with amplitude of 100-200 μV and duration of about 50 msec were recorded, which coincided with the front of BP wave corrected for a 10-msec delay of the pressure transducer...
April 16, 2018: Bulletin of Experimental Biology and Medicine
Sławomir Kujawski, Agnieszka Kujawska, Małgorzata Gajos, Jacek J Klawe, Małgorzata Tafil-Klawe, Katarzyna Mądra-Gackowska, Błażej Stankiewicz, Julia L Newton, Kornelia Kędziora-Kornatowska, Paweł Zalewski
BACKGROUND: Arterial stiffness (AS) is a reduction in the ability of large arteries to readily accommodate the increase in blood ejected from the heart during systole related with aging. Physical exercise is associated with AS reduction. However, it remains controversial as to which modality and intensity (resistance vs aerobic, high vs low) would be the most effective. The aim of these studies is to examine the effects of 3-months sitting callisthenic balance (SCB) and resistance exercise (RET) on aerobic capacity, aortic stiffness and body composition in older participants...
April 12, 2018: Experimental Gerontology
Karin A Garcia, William K Wohlgemuth, Ele Ferrannini, Andrea Mari, Alex Gonzalez, Armando J Mendez, Roberto Bizzotto, Jay S Skyler, Neil Schneiderman, Barry E Hurwitz
AIMS: Sleeping oxygen saturation (SaO2 ) and sleep stage duration have been linked with prediabetic alterations but the pathogenic pathways are not well understood. This study of insulin sensitive and resistant adults examined the effect on postprandial metabolic regulation of repeated mixed-meal challenges of different carbohydrate loading. The aim was to examine whether the relationship between lower sleeping oxygen saturation (SaO2 ) and poorer fasting and postprandial metabolic function may be linked with reduced slow wave sleep (SWS) and rapid eye movement (REM) duration, independent of age, sex and total adiposity...
April 12, 2018: Physiology & Behavior
Ze Tao, Fu Jun Chen, Lin Yi Zhou, Bin Li, Yong Chun Tao, Jun Wang
The interedge coupling is the cardinal characteristic of the narrow quantum spin Hall (QSH) insulator, and thus could bring about exotic transport phenomena. Herein, we present a theoretical investigation of the spin-resolved Andreev reflection (AR) in a QSH insulator strip touching on two neighbouring ferromgnetic insulators and one s-wave superconductor. It is demonstrated that, due
 to the interplay of the interedge coupling and ferromagnetic configuration, there could be not only usual local ARs leading to spin-singlet pairing with the incident electron and Andreev-reflected hole from different spin subbands, but also novel local ARs giving rise to triplet pairing with the same spin...
April 13, 2018: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Yanina Zocalo, Juan M Castro, Victoria Garcia-Espinosa, Santiago Curcio, Pedro Chiesa, Gustavo Giachetto, Edmundo I Cabrera-Fischer, Daniel Bia
High blood pressure states (HBP) would differ in wave components and reflections indexes, which could associate clinical and prognostic implications. AIMS: 1) to characterize the association of aortic wave components and reflection parameters (backward [Pb], forward [Pf], Pb/Pf ratio and augmentation index [AIx]) with demographic, anthropometric, hemodynamic and arterial parameters in healthy children and adolescents; 2) to generate multivariate prediction models for the associations, to contribute to understand main determinants of Pf, Pb, Pb/Pf and AIx; 3) to identify if differences in wave reflection indexes observed in HBP could be explained by differences in the analyzed parameters...
April 12, 2018: Current Hypertension Reviews
Kakulavarapu V Rama Rao, Stephanie Iring, Daniel Younger, Matthew Kuriakose, Maciej Skotak, Eren Alay, Raj K Gupta, Namas Chandra
Blast-induced Traumatic Brain Injury (bTBI) is a leading cause of morbidity in soldiers on the battlefield and in the training sites with long-term neurological and psychological pathologies. Previous studies from our laboratory demonstrated activation of oxidative stress pathways following blast injury, but their distribution among different brain regions and their impact on the pathogenesis of bTBI have not been explored. The present study examined the protein expression of two isoforms: NADPH oxidase 1 and 2 (NOX1, NOX2), corresponding superoxide production, a downstream event of NOX activation, and the extent of lipid peroxidation adducts of 4-hydroxynonenal (4HNE) to a range of proteins...
March 16, 2018: Journal of Neurotrauma
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