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Cross-frequency coupling

Nikola N Radovanović, Siniša U Pavlović, Goran Milašinović, Bratislav Kirćanski, Mirjana M Platiša
We investigated cardio-respiratory coupling in patients with heart failure by quantification of bidirectional interactions between cardiac (RR intervals) and respiratory signals with complementary measures of time series analysis. Heart failure patients were divided into three groups of twenty, age and gender matched, subjects: with sinus rhythm (HF-Sin), with sinus rhythm and ventricular extrasystoles (HF-VES), and with permanent atrial fibrillation (HF-AF). We included patients with indication for implantation of implantable cardioverter defibrillator or cardiac resynchronization therapy device...
2018: Frontiers in Physiology
Keiji Yasuda, Tam Thanh Nguyen, Yoshiyuki Asakura
Cross-sectional area distribution of broadband noise in a sonochemical reactor was measured to estimate reaction fields. A needle-type hydrophone scanned the sonochemical reactor in horizontal and vertical directions at one-millimeter interval. To show an absolute value of broadband noise, average of broadband sound pressure was defined. The distribution of sound pressures at the fundamental and second harmonic frequencies were also measured. In the case of driving frequency at 130 kHz, sonochemical reaction fields were observed in several ellipse shapes...
May 2018: Ultrasonics Sonochemistry
Krishnendu Kundu, Akiva Feintuch, Shimon Vega
Recently it has been shown that experimental ELDOR spectra of amorphous glasses containing free radicals with inhomogeneously broadened EPR spectra can be analyzed using a set of coupled rate equations for the electron polarizations of frequency bins composing these spectra, named the eSD (electron spectral diffusion) model. The rate matrix defining these equations has elements depending on the microwave, the spin lattice relaxation rates and on eSD rate constants responsible for polarization exchange. In this study, we show that in addition to the static dipolar flip-flop terms in the Hamiltonian a zero-quantum electron cross-relaxation mechanism can be responsible for the polarization exchange process in our samples...
March 19, 2018: Journal of Physical Chemistry Letters
Richard S Mills, Heidi Sveistrup
The aims of this study were to (1) characterize anticipatory and reactive postural strategies in typically developing (TD) children and adolescents; (2) determine if TD youth shift from reactive to anticipatory mechanisms based on knowledge of platform movement; and (3) determine whether TD youth further modify postural strategies when additional information about the perturbation is provided. Sixteen typically developing youth aged 7-17 years stood with eyes open on a movable platform that progressively translated anteroposteriorly (20 cm peak-to-peak) through four speeds (0...
March 17, 2018: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
Sven Vanneste, Jae-Jin Song, Dirk De Ridder
Thalamocortical dysrhythmia (TCD) is a model proposed to explain divergent neurological disorders. It is characterized by a common oscillatory pattern in which resting-state alpha activity is replaced by cross-frequency coupling of low- and high-frequency oscillations. We undertook a data-driven approach using support vector machine learning for analyzing resting-state electroencephalography oscillatory patterns in patients with Parkinson's disease, neuropathic pain, tinnitus, and depression. We show a spectrally equivalent but spatially distinct form of TCD that depends on the specific disorder...
March 16, 2018: Nature Communications
Gary Beane, Brendan S Brown, Paul Johns, Tuphan Devkota, Gregory V Hartland
The interaction between plasmonic and excitonic systems and the formation of hybridized states is an area of intense interest, due to the potential to create exotic light-matter states. We report herein coupling between the leaky surface plasmon polariton (SPP) modes of single Ag nanowires and excitons of a cyanine dye (TDBC) in an open nanocavity. Silver nanowires were spin-cast onto glass coverslips, and the wavevector of the leaky SPP mode was measured by back focal plane (BFP) microscopy. Performing these measurements at different wavelengths allows the generation of dispersion curves, which show avoided crossings after deposition of a concentrated TDBC-PVA film...
March 16, 2018: Journal of Physical Chemistry Letters
Kai Sun, Deqiang Yang, Sihao Liu, Tianming Yang
In this paper, a wide-band low cross polarization antenna with a structure of microstrip line coupling to slot line as the balun is proposed. The radiation part of the antenna is fed by two pairs of parallel transmission line via a transition from a slot line which is coupled by a microstrip line. Because it is fed by parallel transmission lines, which is balanced-fed structure, the antenna can achieve an improved low cross-polarization performance. The height of the antenna is 0.146λ0 (λ0 is the wavelength of lowest frequency)...
2018: PloS One
Felix A Blyakhman, Nikita A Buznikov, Tatyana F Sklyar, Alexander P Safronov, Elizaveta V Golubeva, Andrey V Svalov, Sergey Yu Sokolov, Grigory Yu Melnikov, Iñaki Orue, Galina V Kurlyandskaya
Hydrogels are biomimetic materials widely used in the area of biomedical engineering and biosensing. Ferrogels (FG) are magnetic composites capable of functioning as magnetic field sensitive transformers and field assisted drug deliverers. FG can be prepared by incorporating magnetic nanoparticles (MNPs) into chemically crosslinked hydrogels. The properties of biomimetic ferrogels for multifunctional biosensor applications can be set up by synthesis. The properties of these biomimetic ferrogels can be thoroughly controlled in a physical experiment environment which is much less demanding than biotests...
March 15, 2018: Sensors
Anne Keitel, Joachim Gross, Christoph Kayser
During online speech processing, our brain tracks the acoustic fluctuations in speech at different timescales. Previous research has focused on generic timescales (for example, delta or theta bands) that are assumed to map onto linguistic features such as prosody or syllables. However, given the high intersubject variability in speaking patterns, such a generic association between the timescales of brain activity and speech properties can be ambiguous. Here, we analyse speech tracking in source-localised magnetoencephalographic data by directly focusing on timescales extracted from statistical regularities in our speech material...
March 12, 2018: PLoS Biology
David M Harcombe, Michael G Ruppert, Michael R P Ragazzon, Andrew J Fleming
An important issue in the emerging field of multifrequency atomic force microscopy (MF-AFM) is the accurate and fast demodulation of the cantilever-tip deflection signal. As this signal consists of multiple frequency components and noise processes, a lock-in amplifier is typically employed for its narrowband response. However, this demodulator suffers inherent bandwidth limitations as high-frequency mixing products must be filtered out and several must be operated in parallel. Many MF-AFM methods require amplitude and phase demodulation at multiple frequencies of interest, enabling both z -axis feedback and phase contrast imaging to be achieved...
2018: Beilstein Journal of Nanotechnology
Minkyun Noh, Wolfgang Gruber, David L Trumper
We present a new concept of bearingless slice motor that levitates and rotates a ring-shaped solid rotor. The rotor is made of a semi-hard magnetic material exhibiting magnetic hysteresis, such as D2 steel. The rotor is radially biased with a homopolar permanent-magnetic flux, on which the stator can superimpose 2-pole flux to generate suspension forces. By regulating the suspension forces based on position feedback, the two radial rotor degrees of freedom are actively stabilized. The two tilting degrees of freedom and the axial translation are passively stable due to the reluctance forces from the bias flux...
October 2017: IEEE/ASME Transactions on Mechatronics
Kent R Thurber, Thanh-Ngoc Le, Victor Changcoco, David J R Brook
Solid-state dynamic nuclear polarization (DNP) using the cross-effect relies on radical pairs whose electron spin resonance (ESR) frequencies differ by the nuclear magnetic resonance (NMR) frequency. We measure the DNP provided by a new water-soluble verdazyl radical, verdazyl-ribose, under both magic-angle spinning (MAS) and static sample conditions at 9.4 T, and compare it to a nitroxide radical, 4-hydroxy-TEMPO. We find that verdazyl-ribose is an effective radical for cross-effect DNP, with the best relative results for a non-spinning sample...
March 1, 2018: Journal of Magnetic Resonance
Dalila Y Martínez, Kristien Verdonck, Paul M Kaye, Vanessa Adaui, Katja Polman, Alejandro Llanos-Cuentas, Jean-Claude Dujardin, Marleen Boelaert
BACKGROUND: Tegumentary leishmaniasis (TL) is a disease of skin and/or mucosal tissues caused by Leishmania parasites. TL patients may concurrently carry other pathogens, which may influence the clinical outcome of TL. METHODOLOGY AND PRINCIPAL FINDINGS: This review focuses on the frequency of TL coinfections in human populations, interactions between Leishmania and other pathogens in animal models and human subjects, and implications of TL coinfections for clinical practice...
March 2018: PLoS Neglected Tropical Diseases
Stephanie Schoeppe, Corneel Vandelanotte, Amanda L Rebar, Melanie Hayman, Mitch J Duncan, Stephanie J Alley
OBJECTIVES: To compare the frequency of and trends in healthy lifestyle factors between singles and couples. METHODS: Cross-sectional data from annual surveys conducted from 2005-2014 were used. The pooled sample included 15,001 Australian adults (mean age: 52.9 years, 50% male, 74% couples) who participated in the annual Queensland Social Survey via computer-assisted telephone interviews. Relationship status was dichotomised into single and couple. Binary logistic regression was used to assess associations between relationship status, and the frequency of and trends in healthy lifestyle factors...
2018: PloS One
Soheila Samiee, Maxime Lévesque, Massimo Avoli, Sylvain Baillet
Polyrhythmic coupling of oscillatory components in electrophysiological signals results from the interactions between neuronal sub-populations within and between cell assemblies. Since the mechanisms underlying epileptic disorders should affect such interactions, abnormal level of cross-frequency coupling is expected to provide a signal marker of epileptogenesis. We measured phase-amplitude coupling (PAC), a form of cross-frequency coupling between neural oscillations, in a rodent model of mesial temporal lobe epilepsy...
February 24, 2018: Neurobiology of Disease
Christopher K Kovach, Hiroyuki Oya, Hiroto Kawasaki
Most biological signals are non-Gaussian, reflecting their origins in highly nonlinear physiological systems. A versatile set of techniques for studying non-Gaussian signals relies on the spectral representations of higher moments, known as polyspectra, which describe forms of cross-frequency dependence that do not arise in time-invariant Gaussian signals. The most commonly used of these employ the bispectrum. Recently, other measures of cross-frequency dependence have drawn interest in EEG literature, in particular those which address phase-amplitude coupling (PAC)...
February 23, 2018: NeuroImage
Stavros I Dimitriadis, Christos Salis, David Linden
OBJECTIVE: Limitations of the manual scoring of polysomnograms, which include data from electroencephalogram (EEG), electro-oculogram (EOG), electrocardiogram (ECG) and electromyogram (EMG) channels have long been recognized. Manual staging is resource intensive and time consuming, and thus considerable effort must be spent to ensure inter-rater reliability. As a result, there is a great interest in techniques based on signal processing and machine learning for a completely Automatic Sleep Stage Classification (ASSC)...
January 31, 2018: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
Stavros I Dimitriadis, Panagiotis G Simos, Jack Μ Fletcher, Andrew C Papanicolaou
Neuroimaging studies have identified a variety of structural and functional connectivity abnormalities in students experiencing reading difficulties. The present study adopted a novel approach to assess the dynamics of resting-state neuromagnetic recordings in the form of symbolic sequences (i.e., repeated patterns of neuromagnetic fluctuations within and/or between sensors). Participants were 25 students experiencing severe reading difficulties (RD) and 27 age-matched non-impaired readers (NI) aged 7-14 years...
February 21, 2018: International Journal of Psychophysiology
Jérôme Morelle, Pascal Claquin
Diatoms account for about 40% of primary production in highly productive ecosystems. The development of a new generation of fluorometers has made it possible to improve estimation of the electron transport rate from photosystem II, which, when coupled with the carbon incorporation rate enables estimation of the electrons required for carbon fixation. The aim of this study was to investigate the daily dynamics of these electron requirements as a function of the diel light cycle in three relevant diatom species and to apprehend if the method of estimating the electron transport rate can lead to different pictures of the dynamics...
February 23, 2018: Photosynthesis Research
Elinor Tzvi, Leon J Bauhaus, Till U Kessler, Matthias Liebrand, Malte Wöstmann, Ulrike M Krämer
Cross-frequency coupling is suggested to serve transfer of information between wide-spread neuronal assemblies and has been shown to underlie many cognitive functions including learning and memory. In previous work, we found that alpha (8 - 13 Hz) - gamma (30 - 48 Hz) phase amplitude coupling (αγPAC) is decreased during sequence learning in bilateral frontal cortex and right parietal cortex. We interpreted this to reflect decreased demands for visuo-motor mapping once the sequence has been encoded. In the present study, we put this hypothesis to the test by adding a "simple" condition to the standard serial reaction time task (SRTT) with minimal needs for visuo-motor mapping...
February 20, 2018: Neurobiology of Learning and Memory
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