Atypical interference control in children with AD/HD with elevated theta/beta ratio

The theta/beta ratio (TBR) is a major area of interest within electroencephalogram (EEG) research in AD/HD. While researchers suggest a prognostic role for TBR in AD/HD, its relationship to behavior remains uncertain. Recent evidence suggests that elevated TBR in AD/HD may be related to atypical inhibition, particularly at an attentional level. This study aimed to examine the performance on three inhibitory tasks of children with AD/HD. Fifty-eight children with AD/HD participated, divided into an elevated TBR (ET) group and a control group (CT). A behavioral disassociation was found − compared to CT, ET showed more difficulty in inhibiting surrounding stimuli but had less day-to-day inhibitory issues measured by BRIEF. There was no significant group difference on response inhibition. The results support the prognostic value of TBR in AD/HD. Elevated TBR may be an inhibitory biomarker; further studies are needed to explore the behavioral implications in patients without elevated TBR

Electroencephalogram Theta/Beta Ratio and Spectral Power Correlates of Executive Functions in Children and Adolescents With AD/HD

OBJECTIVE: The electroencephalogram (EEG) has been widely used in AD/HD research. The current study firstly aimed to replicate a recent trend related to EEG theta/beta ratio (TBR) in children and adolescents. Also, the study aimed to examine the value of resting EEG activity as biomarkers for executive function (EF) in participants with AD/HD. METHOD: Fifty-three participants with AD/HD and 37 healthy controls were recruited. Resting EEG was recorded with eyes closed. Participants with AD/HD additionally completed EF tasks via the Cambridge Neuropsychological Test Automated Battery. RESULTS: TBR did not differ between groups; however, TBR was positively correlated with inattentive symptoms in AD/HD. Other correlations were found between EEG activity and neuropsychological functions including spatial planning and decision making in the AD/HD group. CONCLUSION: The results do not support the diagnostic value of TBR. Instead, given the heterogeneous features, the results support the prognostic value of EEG in AD/HD

A numerical study for dielectric constant profile of aqueous solvent in ionic solution radiated by high-intensity electric pulses

In this paper, a mathematical physics model is set up to study dielectric constant profile of aqueous solvent in ionic solution, to revise Brownian dynamics simulation in ionic solution by considering time-variant dielectric constant profile with change in ion positions, and to study the effect of high-intensity electric pulses on the profile. The validation of the model is confirmed with verification calculations. By means of the proposed model, dielectric constant profiles in calcium chloride and sodium chloride solutions and their response to pulses are simulated. Based on numerical results, dielectric constants of aqueous solvent spatially vary instead of being the same value in ionic solutions. And the profiles are variant with time due to ion motion in solutions. From the profiles, overall dielectric constant in calcium chloride solution is lower than that in sodium chloride solution. And overall dielectric constant decreases with increment of solution concentration. In addition, the results show that influence on the profiles depends on solution concentration and field intensity of the pulse. The profile in solutions with low concentration is more vulnerable to the pulse than that with high concentration. And overall dielectric constant decreases dramatically as field intensity increases. Those understandings provide basis for application of pulses in biomedical engineering at the molecular level. Meanwhile, pulse radiation provides a potential way to constrain water molecules at room temperature reflected by significantly reducing dielectric constant, and to lower absorption loss of electromagnetic field in millimeter and far infrared band

Designing a Water-Immersed Rectangular Horn Antenna for Generating Underwater OAM Waves

In order to extend the applications of vortex waves, we propose a water-immersed rectangular horn antenna array for generating underwater vortex waves carrying the orbital angular momentum (OAM). Firstly, a single dielectric-loaded rectangular horn antenna with the central frequency of 2.6 GHz was designed for generating underwater electromagnetic (EM) waves. Due to the supplementing dielectric-loaded waveguide in this single antenna, the problems with difficult sealing and fixation of the feed probe could be solved effectively. The simulation results show that it has a good impedance characteristics (S11 < −10 dB) and reasonable losses (less than 3.5 dB total for two antennas and a coaxial line) from 2.5 GHz to 2.7 GHz. Experiments on the single antenna were also carried out, which agree well with the simulations. Based on the designed single antenna, the water-immersed rectangular horn antenna array was proposed, and the phase gradient from 0~2π was fed to the horn antennas for generating underwater OAM waves. The simulation results demonstrate high fidelity of the generated OAM waves from the intensity and phase distributions. The purity of the generated OAM modes was also investigated and further verifies the high fidelity of the generated OAM waves. The generated high-quality OAM waves meet the requirements for underwater applications of OAM, such as underwater communication and underwater imaging

Electroencephalogram theta/beta ratio and spectral power correlates of executive functions in children and adolescents with AD/HD

Objective: The electroencephalogram (EEG) has been widely used in AD/HD research. The current study firstly aimed to replicate a recent trend related to EEG theta/beta ratio (TBR) in children and adolescents. Also, the study aimed to examine the value of resting EEG activity as biomarkers for executive function (EF) in participants with AD/HD. Method: Fifty-three participants with AD/HD and 37 healthy controls were recruited. Resting EEG was recorded with eyes closed. Participants with AD/HD additionally completed EF tasks via the Cambridge Neuropsychological Test Automated Battery. Results: TBR did not differ between groups; however, TBR was positively correlated with inattentive symptoms in AD/HD. Other correlations were found between EEG activity and neuropsychological functions including spatial planning and decision making in the AD/HD group. Conclusion: The results do not support the diagnostic value of TBR. Instead, given the heterogeneous features, the results support the prognostic value of EEG in AD/HD