Construction and analysis of cortical–muscular functional network based on EEG-EMG coherence using wavelet coherence

AbstractReactive molecular additives have often been employed to tailor the mechanical properties of epoxy resins. In addition, several studies have reported improved electrical properties in such systems, where the network architecture and included function groups have been modified through the use of so-called functional network modifier (FNM) molecules. The study reported here set out to investigate the effect of a glycidyl polyhedral oligomeric silsesquioxane (GPOSS) FNM on the cross-linking reactions, glass transition, breakdown strength and dielectric properties of an amine-cured epoxy resin system. Since many previous studies have considered POSS to act as an inorganic filler, a key aim was to consider the impact of GPOSS addition on the stoichiometry of curing. Fourier transform infrared spectroscopy revealed significant changes in the cross-linking reactions that occur if appropriate stoichiometric compensation is not made for the additional epoxide groups present on the GPOSS. These changes, in concert with the direct effect of the GPOSS itself, influence the glass transition temperature, dielectric breakdown behaviour and dielectric response of the system. Specifically, the work shows that the inclusion of GPOSS can result in beneficial changes in electrical properties, but that these gains are easily lost if consequential changes in the matrix polymer are not appropriately counteracted. Nevertheless, if the system is appropriately optimized, materials with pronounced improvements in technologically important characteristics can be designed.

Download Full-text

Alzheimer’s Disease Progressively Reduces Visual Functional Network Connectivity

Journal of Alzheimer s Disease Reports ◽

10.3233/adr-210017 ◽

2021 ◽

pp. 1-14

Author(s):

Jie Huang ◽

Paul Beach ◽

Andrea Bozoki ◽

David C. Zhu

Keyword(s):

Visual Cortex ◽

Lower Order ◽

Resting State ◽

Visual Processing ◽

Network Connectivity ◽

Higher Order ◽

Functional Network ◽

Functional Networks ◽

The Face ◽

Processing Network

Background: Postmortem studies of brains with Alzheimer’s disease (AD) not only find amyloid-beta (Aβ) and neurofibrillary tangles (NFT) in the visual cortex, but also reveal temporally sequential changes in AD pathology from higher-order association areas to lower-order areas and then primary visual area (V1) with disease progression. Objective: This study investigated the effect of AD severity on visual functional network. Methods: Eight severe AD (SAD) patients, 11 mild/moderate AD (MAD), and 26 healthy senior (HS) controls undertook a resting-state fMRI (rs-fMRI) and a task fMRI of viewing face photos. A resting-state visual functional connectivity (FC) network and a face-evoked visual-processing network were identified for each group. Results: For the HS, the identified group-mean face-evoked visual-processing network in the ventral pathway started from V1 and ended within the fusiform gyrus. In contrast, the resting-state visual FC network was mainly confined within the visual cortex. AD disrupted these two functional networks in a similar severity dependent manner: the more severe the cognitive impairment, the greater reduction in network connectivity. For the face-evoked visual-processing network, MAD disrupted and reduced activation mainly in the higher-order visual association areas, with SAD further disrupting and reducing activation in the lower-order areas. Conclusion: These findings provide a functional corollary to the canonical view of the temporally sequential advancement of AD pathology through visual cortical areas. The association of the disruption of functional networks, especially the face-evoked visual-processing network, with AD severity suggests a potential predictor or biomarker of AD progression.

Download Full-text

Market volatility and illiquidity during the COVID-19 outbreak: Evidence from the Saudi stock exchange through the Wavelet coherence approaches

The North American Journal of Economics and Finance ◽

10.1016/j.najef.2021.101521 ◽

2021 ◽

pp. 101521

Author(s):

Kais Tissaoui ◽

Besma Hkiri ◽

Waleed Alghassab ◽

Mariem Talbi ◽

Khaled Issa Alfreahat

Keyword(s):

Stock Exchange ◽

Market Volatility ◽

Wavelet Coherence

Download Full-text

Altered resting‐state functional network connectivity in profound sensorineural hearing loss infants within an early sensitive period: A group ICA study

Human Brain Mapping ◽

10.1002/hbm.25548 ◽

2021 ◽

Author(s):

Shanshan Wang ◽

Boyu Chen ◽

Yalian Yu ◽

Huaguang Yang ◽

Wenzhuo Cui ◽

...

Keyword(s):

Hearing Loss ◽

Sensorineural Hearing Loss ◽

Resting State ◽

Network Connectivity ◽

Sensorineural Hearing ◽

Functional Network ◽

Sensitive Period ◽

Functional Network Connectivity ◽

Group Ica

Download Full-text

cccccSource-level EEG and graph theory reveal widespread functional network alterations in focal epilepsy

Clinical Neurophysiology ◽

10.1016/j.clinph.2021.04.008 ◽

2021 ◽

Author(s):

Christoffer Hatlestad-Hall ◽

Ricardo Bruña ◽

Marte Roa Syvertsen ◽

Aksel Erichsen ◽

Vebjørn Andersson ◽

...

Keyword(s):

Graph Theory ◽

Focal Epilepsy ◽

Functional Network

Download Full-text

Effect of economic indicators, biomass energy on human development in China

Energy & Environment ◽

10.1177/0958305x211022040 ◽

2021 ◽

pp. 0958305X2110220

Author(s):

Ngo Thai Hung

Keyword(s):

Human Development ◽

Global Financial Crisis ◽

Trade Openness ◽

Biomass Energy ◽

Wavelet Coherence ◽

Causality Test ◽

Frequency Domains ◽

Bidirectional Relationship ◽

The Global Financial Crisis

Previous studies ignored the distinction between short, medium, and long term by decomposing macroeconomic variables and human development index at different time scales. We re-visit the causal association between biomass energy (BIO), economic growth (GDP), trade openness (TRO), industrialization (IND), foreign direct investment (FDI), and human development (HDI) in China on a quarterly scale by scale basis for the period 1990 to 2019 using the tools of wavelet, i.e., wavelet correlation, wavelet coherence and scale by scale Granger causality test. The main findings uncover that IND, TRO, GDP, and BIO positively drive the HDI at low and medium frequencies, while FDI negatively impacts HDI during the sample period. Additionally, there is a bidirectional relationship between GDP and HDI at different time and frequency domains. Specifically, we discover that the positive co-movement is more robust in the aftermath of the global financial crisis, particularly for HDI, BIO, GDP, and TRO at medium frequencies throughout the period under research. Our empirical insights have significant implications for achieving human development sustainability in China.

Download Full-text