Using the nonlinear control of anaesthesia-induced hypersensitivity of EEG at burst suppression level to test the effects of radiofrequency radiation on brain function

Background In this study, investigating the effects of mobile phone radiation on test animals, eleven pigs were anaesthetised to the level where burst-suppression pattern appears in the electroencephalogram (EEG). At this level of anaesthesia both human subjects and animals show high sensitivity to external stimuli which produce EEG bursts during suppression. The burst-suppression phenomenon represents a nonlinear control system, where low-amplitude EEG abruptly switches to very high amplitude bursts. This switching can be triggered by very minor stimuli and the phenomenon has been described as hypersensitivity. To test if also radio frequency (RF) stimulation can trigger this nonlinear control, the animals were exposed to pulse modulated signal of a GSM mobile phone at 890 MHz. In the first phase of the experiment electromagnetic field (EMF) stimulation was randomly switched on and off and the relation between EEG bursts and EMF stimulation onsets and endpoints were studied. In the second phase a continuous RF stimulation at 31 W/kg was applied for 10 minutes. The ECG, the EEG, and the subcutaneous temperature were recorded. Results No correlation between the exposure and the EEG burst occurrences was observed in phase I measurements. No significant changes were observed in the EEG activity of the pigs during phase II measurements although several EEG signal analysis methods were applied. The temperature measured subcutaneously from the pigs' head increased by 1.6°C and the heart rate by 14.2 bpm on the average during the 10 min exposure periods. Conclusion The hypothesis that RF radiation would produce sensory stimulation of somatosensory, auditory or visual system or directly affect the brain so as to produce EEG bursts during suppression was not confirmed.BioMed Central Open acces

State Of the Art Report in the fields of numerical analysis and scientific computing. Final version as of 16/02/2020 deliverable D4.1 of the HORIZON 2020 project EURAD.: European Joint Programme on Radioactive Waste Management

Document information Project Acronym EURAD Project Title European Joint Programme on Radioactive Waste Management Project Type European Joint Programme (EJP) EC grant agreement No. 847593 Project starting / end date 1 st June 2019-30 May 2024 Work Package No. 4 Work Package Title Development and Improvement Of NUmerical methods and Tools for modelling coupled processes Work Package Acronym DONUT Deliverable No. 4.

Non-linear algorithms for processing biological signals

This paper illustrates different approaches to the analysis of biological signals based on non-linear methods. The performance of such approaches, despite the greater methodological and computational complexity is, in many instances, more successful compared to linear approaches, in enhancing important parameters for both physiological studies and clinical protocols. The methods introduced employ median filters for pattern recognition, adaptive segmentation, data compression, prediction and data modelling as well as multivariate estimators in data clustering through median learning vector quantizers. Another approach described uses Wiener-Volterra kernel technique to obtain a satisfactory estimation and causality test among EEG recordings. Finally, methods for the assessment of non-linear dynamic behaviour are discussed and applied to the analysis of heart rate variability signal. In this way invariant parameters are studied which describe non-linear phenomena in the modelling of the physiological systems under investigation

Acidity of Strong Acids in Water and Dimethyl Sulfoxide

Careful analysis and comparison of the available acidity data of HCl, HBr, HI, HClO₄, and CF₃SO₃H in water, dimethyl sulfoxide (DMSO), and gas-phase has been carried out. The data include experimental and computational p<i>K</i>_a and gas-phase acidity data from the literature, as well as high-level computations using different approaches (including the W1 theory) carried out in this work. As a result of the analysis, for every acid in every medium, a recommended acidity value is presented. In some cases, the currently accepted p<i>K</i>_a values were revised by more than 10 orders of magnitude

Superacidity of <i>closo</i>-Dodecaborate-Based Brønsted Acids: a DFT Study

The structures and intrinsic gas-phase acidities (GA) of some dodecaborane acids, the derivatives of YB₁₂H₁₁H (Y <b>=</b> PF₃, NH₃, NF₃, NMe₃), B₁₂H₁₂H₂, and B₁₂H₁₂H^– (HA, H₂A, and HA^–, respectively) have been computationally explored with DFT B3LYP method at the 6-311+G** level of theory as new possible directions of creating superstrong Brønsted acids. Depending on the nature and number of the substituents different protonation geometries were investigated. In general, the GA values of the neutral systems varied according to the substituents in the following order: CF₃ < F < Cl and in case of anionic acids: CF₃ < Cl < F. The dodecatrifluoromethyl derivative of H₂A, B₁₂(CF₃)₁₂H₁H₂, emerges as the strongest among the considered acids and is expected to be in the gas phase at least as strong as the undecatrifluoromethyl carborane, CB₁₁(CF₃)₁₁H₁H. The GA values of the respective monoanionic forms of the considered acids all, but the (CF₃)₁₁ derivative, remained higher than the widely used threshold of superacidity. The HA derivatives’ (Y <b>=</b> PF₃, NF₃) GA’s were approximately in the same range as the H₂A acids’. In the case Y <b>=</b> NH₃ or NMe₃ the GA values were significantly higher. Also, the p<i>K</i>_a values of B₁₂H₁₂H₂, CB₁₁H₁₂H, and their perfluorinated derivatives in 1,2-dichloroethane (DCE) were estimated with SMD and cluster-continuum model calculations. The obtained estimates of p<i>K</i>_a values of the perfluorinated derivatives are by around 30 units lower than that of trifluoromethylsulfonylimide, making these acids the strongest ever predicted in solution. The derivatives of B₁₂H₁₂H₂ are as a rule not significantly weaker acids than the respective derivatives of CB₁₁H₁₂H. This is important for expanding practical applicability of this type of acids and their anions, as they are synthetically much more accessible than the corresponding CB₁₁H₁₂^– derivatives