22 research outputs found
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, HClO<sub>4</sub>, and CF<sub>3</sub>SO<sub>3</sub>H
in water, dimethyl sulfoxide (DMSO), and gas-phase has been carried
out. The data include experimental and computational p<i>K</i><sub>a</sub> 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><sub>a</sub> 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 YB<sub>12</sub>H<sub>11</sub>H (Y <b>=</b> PF<sub>3</sub>, NH<sub>3</sub>, NF<sub>3</sub>, NMe<sub>3</sub>), B<sub>12</sub>H<sub>12</sub>H<sub>2</sub>, and B<sub>12</sub>H<sub>12</sub>H<sup>–</sup> (HA, H<sub>2</sub>A, and HA<sup>–</sup>, 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:
CF<sub>3</sub> < F < Cl and in case of anionic acids: CF<sub>3</sub> < Cl < F. The dodecatrifluoromethyl derivative of H<sub>2</sub>A, B<sub>12</sub>(CF<sub>3</sub>)<sub>12</sub>H<sub>1</sub>H<sub>2</sub>, 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, CB<sub>11</sub>(CF<sub>3</sub>)<sub>11</sub>H<sub>1</sub>H. The GA values of the respective monoanionic forms of the considered
acids all, but the (CF<sub>3</sub>)<sub>11</sub> derivative, remained
higher than the widely used threshold of superacidity. The HA derivatives’
(Y <b>=</b> PF<sub>3</sub>, NF<sub>3</sub>) GA’s were
approximately in the same range as the H<sub>2</sub>A acids’.
In the case Y <b>=</b> NH<sub>3</sub> or NMe<sub>3</sub> the
GA values were significantly higher. Also, the p<i>K</i><sub>a</sub> values of B<sub>12</sub>H<sub>12</sub>H<sub>2</sub>,
CB<sub>11</sub>H<sub>12</sub>H, 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><sub>a</sub> 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
B<sub>12</sub>H<sub>12</sub>H<sub>2</sub> are as a rule not significantly
weaker acids than the respective derivatives of CB<sub>11</sub>H<sub>12</sub>H. 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 CB<sub>11</sub>H<sub>12</sub><sup>–</sup> derivatives