Read by QxMD icon Read

Cross frequency coupling

Markus Göttlicher, Marcus Rohnke, Yannik Moryson, Jürgen Thomas, Joachim Sann, Anja Lode, Matthias Schumacher, Romy Schmidt, Stefan Pilz, Annett Gebert, Thomas Gemming, Jürgen Janek
BACKGROUND: Surface functionalization of orthopedic implants with pharmaceutically active agents is a modern approach to enhance osseointegration in systemically altered bone. A local release of strontium, a verified bone building therapeutic agent, at the fracture site would diminish side effects, which could occur otherwise by oral administration. Strontium surface functionalization of specially designed titanium-niobium (Ti-40Nb) implant alloy would provide an advanced implant system that is mechanically adapted to altered bone with the ability to stimulate bone formation...
2017: Biomaterials Research
Xianshun Ming, Xinyu Liu, Liqun Sun, Willie J Padilla
We develop the theory of all-dielectric absorbers based on temporal coupled mode theory (TCMT), with parameters extracted from eigenfrequency simulations. An infinite square array of cylindrical resonators embedded in air is investigated, and we find that it supports two eigenmodes of opposite symmetry that are each responsible for half of the total absorption. The even and odd eigenmodes are found to be the hybrid electric (EH111) and hybrid magnetic (HE111) waveguide modes of a dielectric wire of circular cross section, respectively...
October 2, 2017: Optics Express
Chenyu Li, Chun-Chieh Chang, Qingli Zhou, Cunlin Zhang, Hou-Tong Chen
We investigate edge-coupling of twisted split-ring resonator (SRR) pairs in the terahertz (THz) frequency range. Using a simple coupled-resonator model we show that such a system exhibits resonance splitting and cross-polarization conversion. Numerical simulations and experimental measurements agree well with theoretical calculations, verifying the resonance splitting as a function of the coupling strength given by the SRR separation. We further show that a metal ground plane can be integrated to significantly enhance the resonance coupling, which enables the effective control of resonance splitting and the efficiency and bandwidth of the cross-polarization conversion...
October 16, 2017: Optics Express
Yanzhang Lin, Haizi Yao, Xuewei Ju, Ying Chen, Shuncong Zhong, Xiangfeng Wang
We report on the fabrication and transmission properties of free-standing single-layer and double-layer THz bandpass filters. These filters are fabricated on aluminum foils using femtosecond laser micro-machining. The aluminum foils are periodically patterned with cross apertures with a total area of 1.75×1.75 cm(2), also known as frequency-selective surfaces. Their terahertz transmission properties were simulated using the FDTD method and measured using a time-domain terahertz spectroscopy system. The simulation results agree with the measurements results very well...
October 16, 2017: Optics Express
Ning Cheng, Qun Li, Sitong Wang, Rubin Wang, Tao Zhang
Cross-frequency phase-amplitude coupling (PAC) in neuronal oscillations network plays an important functional role in large scale neuronal communication and neuronal encoding. In the present study, a novel approach named permutation mutual information (PMI) was applied in measuring PAC. It is derived from the permutation entropy based on the mutual information theory, by which the mutual information of permutations of two time series can be evaluated. In order to verify the ability of PMI, a numerical test was performed by using both simulation data and experimental data...
October 5, 2017: Brain Topography
Sima Pouyandeh, Stefano Iubini, Sandro Jurinovich, Yasser Omar, Benedetta Mennucci, Francesco Piazza
In this paper we work out a parameterization of the environment noise within the Haken-Strobl-Reinenker (HSR) model for the PE545 light-harvesting complex based on atomic-level quantum mechanics/molecular mechanics (QM/MM) simulations. We use this approach to investigate the role of different auto- and cross-correlations in the HSR noise tensor, confirming that site-energy autocorrelations (pure dephasing) terms dominate the noise-induced exciton mobility enhancement, followed by site energy-coupling cross-correlations for specific triplets of pigments...
October 4, 2017: Physical Biology
Karen M Hampanda, Christine Tagliaferri Rael
HIV-positive pregnant and postpartum women's status disclosure to male sexual partners is associated with improved HIV and maternal and child health outcomes. Yet, status disclosure remains a challenge for many women living with HIV in sub-Saharan Africa, particularly those who are fearful of violence. The objective of the present study is to advance the current understanding of the relationship between intimate partner violence against women and their HIV status disclosure behaviors. We specifically evaluate how the severity, frequency, and type of violence against postpartum HIV-positive women affect status disclosure within married/cohabiting couples...
October 3, 2017: AIDS and Behavior
Jonathan Daume, Sebastian Graetz, Thomas Gruber, Andreas K Engel, Uwe Friese
Working memory (WM) maintenance of sensory information has been associated with enhanced cross-frequency coupling between the phase of low frequencies and the amplitude of high frequencies, particularly in medial temporal lobe (MTL) regions. It has been suggested that these WM maintenance processes are controlled by areas of the prefrontal cortex (PFC) via frontotemporal phase synchronisation in low frequency bands. Here, we investigated whether enhanced cognitive control during audiovisual WM as compared to visual WM alone is associated with increased low-frequency phase synchronisation between sensory areas maintaining WM content and areas from PFC...
October 3, 2017: Scientific Reports
Helena J V Rutherford, Xiaoyue M Guo, Jia Wu, Kelsey M Graber, Nathan J Hayes, Kevin A Pelphrey, Linda C Mayes
Recent research has suggested a role for the hormone oxytocin in social cognition and behavior. Administration of intranasal oxytocin modulates multiple brain regions during experimental tasks; however, the neural mechanisms that underscore the changes associated with oxytocin administration are yet to be fully elucidated. In a double-blind placebo controlled design using electroencephalography, the effects of intranasal oxytocin on neural oscillations (delta, theta, alpha, beta) and their coupling during the resting state were examined...
September 28, 2017: International Journal of Psychophysiology
Mickaël D Chekroun, Dmitri Kondrashov
Harmonic decompositions of multivariate time series are considered for which we adopt an integral operator approach with periodic semigroup kernels. Spectral decomposition theorems are derived that cover the important cases of two-time statistics drawn from a mixing invariant measure. The corresponding eigenvalues can be grouped per Fourier frequency and are actually given, at each frequency, as the singular values of a cross-spectral matrix depending on the data. These eigenvalues obey, furthermore, a variational principle that allows us to define naturally a multidimensional power spectrum...
September 2017: Chaos
Vasily Grigorovsky, Berj L Bardakjian
OBJECTIVE: One of the features used in the study of hyperexcitablility are high frequency oscillations (HFOs, >80Hz). HFOs have been reported in the electrical rhythms of the brain's neuro-glial networks under physiological and pathological conditions. Cross-frequency coupling (CFC) of HFOs with low frequency rhythms was used to identify pathologic HFOs (pHFOs) (i) in the epileptogenic zones of epileptic patients, and (ii) as a biomarker for the severity of seizure-like events in genetically modified rodent models...
September 28, 2017: IEEE Transactions on Bio-medical Engineering
Thomas F Dixon, Lachlan W Russell, Ana Andres-Arroyo, Peter J Reece
We experimentally investigate the influence of geometric aberrations in optical tweezers using back focal plane interferometry. We found that the introduction of coma aberrations causes significant modification to the Brownian motion of the trapped particle, producing an apparent cross-coupling between the in-plane aberrated axis and the weaker propagation axis. This coupling is evidenced by the emergence of a second dominant low frequency Lorentzian feature in the position power spectral density. The effect on Brownian motion was confirmed using a secondary unaberrated probe beam, ruling out the possibility of systematic optical effects related to the detection system...
August 1, 2017: Optics Letters
Faizan Raza, DaBin Yim, Jung Hyun Park, Hye-In Kim, Su-Ji Jeon, Jong-Ho Kim
Effective photocatalysts and their surface engineering are essential for the efficient conversion of solar energy into chemical energy in photocatalyzed organic transformations. Herein, we report an effective approach for structuring Pd nanoparticles (NPs) on exfoliated 2H-WS2 nanosheets (WS2/PdNPs), resulting in hybrids with extraordinary photocatalytic activity in Suzuki reactions under visible light. Pd NPs of different sizes and densities, which can modulate the photocatalytic activity of the as-prepared WS2/PdNPs, were effectively structured on the basal plane of 2H-WS2 nanosheets via a sonic wave-assisted nucleation method without any reductants at room temperature...
October 5, 2017: Journal of the American Chemical Society
Florian Puls, Nils Richter, Olga Kataeva, Hans-Joachim Knölker
We have developed a short and simple synthesis of tetranuclear palladium(II) complexes which have been structurally confirmed by X-ray analysis. These complexes were formed in about 30 % overall yield by spontaneous metalation of dimethylaminoarene derivatives and exhibit a high stability. We have studied the utility of the tetranuclear palladium(II) complexes as precatalysts for Mizoroki-Heck and Suzuki-Miyaura cross coupling reactions. Our novel complexes show excellent catalytic activities with high turnover numbers and high turnover frequencies (e...
September 21, 2017: Chemistry: a European Journal
Muhammad Bilal, Abdul Haseeb, Aleena Zehra Merchant, Abdur Rehman, Mohammad Hussham Arshad, Maarij Malik, Asad Hammad Ur Rehman, Pallavi Rani, Emaan Farhan, Taha S Rehman, Umer Sultan Shamsi, Sadia Aminah
BACKGROUND: Osteoporosis is a growing health problem around the world. The increasing incidence of osteoporotic fractures coupled with the lack of knowledge about the disease in the general community means that the disease is continuously increasing the burden on health sector and the general population. The purpose of the study is to assess knowledge, attitudes and practices about osteoporosis among female medical school entrants in Karachi. METHODS: This is a descriptive cross-sectional study conducted amongst 400 female medical school entrants of DOW University of Health Sciences (DUHS) and Jinnah Sindh Medical University (JSMU)...
2017: Asia Pacific Family Medicine
Biswanath Bhoi, Bosung Kim, Junhoe Kim, Young-Jun Cho, Sang-Koog Kim
We experimentally demonstrate strongly enhanced coupling between excited magnons in an Yttrium Iron Garnet (YIG) film and microwave photons in an inverted pattern of split-ring resonator (noted as ISRR). The anti-crossing effects of the ISRR's photon mode and the YIG's magnon modes were found from |S21|-versus-frequency measurements for different strengths and directions of externally applied magnetic fields. The spin-number-normalized coupling strength (i.e. single spin-photon coupling) [Formula: see text] was determined to 0...
September 20, 2017: Scientific Reports
A Ahnaou, H Huysmans, R Biermans, N V Manyakov, W H I M Drinkenburg
Recently, the N-methyl-d-aspartate-receptor (NMDAR) antagonist ketamine has emerged as a fast-onset mechanism to achieve antidepressant activity, whereas its psychomimetic, dissociative and amnestic effects have been well documented to pharmacologically model schizophrenia features in rodents. Sleep-wake architecture, neuronal oscillations and network connectivity are key mechanisms supporting brain plasticity and cognition, which are disrupted in mood disorders such as depression and schizophrenia. In rats, we investigated the dynamic effects of acute and chronic subcutaneous administration of ketamine (2...
September 19, 2017: Translational Psychiatry
Marios Antonakakis, Stavros I Dimitriadis, Michalis Zervakis, Andrew C Papanicolaou, George Zouridakis
Functional brain connectivity networks exhibit "small-world" characteristics and some of these networks follow a "rich-club" organization, whereby a few nodes of high connectivity (hubs) tend to connect more densely among themselves than to nodes of lower connectivity. The Current study followed an "attack strategy" to compare the rich-club and small-world network organization models using Magnetoencephalographic (MEG) recordings from mild traumatic brain injury (mTBI) patients and neurologically healthy controls to identify the topology that describes the underlying intrinsic brain network organization...
2017: Frontiers in Human Neuroscience
Sabina Easmin, Md Zaidul Islam Sarker, Kashif Ghafoor, Sahena Ferdosh, Juliana Jaffri, Md Eaqub Ali, Hamed Mirhosseini, Fahad Y Al-Juhaimi, Vikneswari Perumal, Alfi Khatib
Phaleria macrocarpa, known as "Mahkota Dewa", is a widely used medicinal plant in Malaysia. This study focused on the characterization of α-glucosidase inhibitory activity of P. macrocarpa extracts using Fourier transform infrared spectroscopy (FTIR)-based metabolomics. P. macrocarpa and its extracts contain thousands of compounds having synergistic effect. Generally, their variability exists, and there are many active components in meager amounts. Thus, the conventional measurement methods of a single component for the quality control are time consuming, laborious, expensive, and unreliable...
April 2017: Journal of Food and Drug Analysis
Fatima Dahmani, Souad Benkirane, Jaafar Kouzih, Aziz Woumki, Hassan Mamad, Azlarab Masrar
Hemoglobinopathies are congenital disorders resultimg from hemoglobin abnormalities. Major forms are often severe, their management is difficult and associated with a great psychosocial impact on patients and their families. They are classified as rare diseases and are still insufficiently known by health professionals. This lack of knowledge is at the origin of diagnostic errors, delay in their management and therefore high morbidity and mortality rate for these patients. In 2008, the World Health Organization (WHO) has published data on hemoglobinopathies epidemiology: more than 330...
2017: Pan African Medical Journal
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"