Françoise Paladian

Microwave Irradiation Affects Gene Expression in Plants

The physiological impact of non-ionizing radiation has long been considered negligible. However, here we use a carefully calibrated stimulation system that mimics the characteristics (isotropy and homogeneity) of electromagnetic fields present in the environment to measure changes in a molecular marker (mRNA encoding the stress-related bZIP transcription factor), and show that low amplitude, short duration, 900 MHz EMF evokes the accumulation of this mRNA. Accumulation is rapid (peaking 5-15 min after stimulation) and strong (3.5-fold), and is similar to that evoked by injurious stimuli.

An Improved Method for the Calculation of the Internal Impedances of Solid and Hollow Conductors With the Inclusion of Proximity Effect

We present a new method for the evaluation of the per unit length (p.u.l.) internal impedances of solid and hollow conductors. Our method is semianalytical, and takes into account the proximity effect arising from currents mutually induced by nearby conductors which, in turn, modify their internal current density distribution and, hence, their impedance. We eventually apply the developed method to the case of a three-core cable and we calculate the voltages induced in its screens by a lightning current.

Plants Respond to GSM-Like Radiations

In this article, we propose that an organism’s general architecture is of primary importance for its ability to perceive electromagnetic radiation. Animals develop mainly as volumes for internal assimilation and appendages to increase their mobility, while plants develop as surfaces to optimize interaction with the environment. As a consequence, the proportion of cells directly interacting with EMF radiation at the organism interface is much higher in plants than it is in animals, making them especially suited to study EMF effects on life.

Modeling complex systems for EMC applications by considering uncertainties

The objective of this work is to present a new approach to the random modeling of complex systems in ElectoMagnetic Compatibility (EMC). This contribution aims to compute high orders statistics and study the impact of parameter uncertainties on various EMC topics including transmission lines, radiation and immunity problems. The agreement between results from the Stochastic Collocation (SC) method and Monte-Carlo (MC) simulations guarantee the SC accuracy and robustness. The combination of SC with computations from analytical and tridimensional numerical models (Finite Difference in Time Domain) underlines its advantages (efficiency, non-intrusive integration).

Mode Stirred Reverberation Chamber (MSRC): a large and efficient tool to lead high frequency bioelectromagnetic in vitro experimentation

An important aspect of the studies undertaken in bioelectromagnetism relates to the choice of exposure facility. The characteristics of a real electromagnetic environment are far more complex compared to the one plane wave irradiation set-up used in the majority of bioelectromagnetic studies. Moreover, biological requirements should represent the starting point in the design of an in vitro exposure system. Indeed it is important to avoid altering the electromagnetic properties of the exposure system in the presence of biological equipments. Related to these two essential points, this article contributes to show the advantages of a Mode Stirred Reverberation Chamber (MSRC) to guarantee a controlled electromagnetic environment around biological materials for in vitro experimentation. An example of irradiation of in vitro human skin cells cultures is considered to illustrate this paper. In order to show that the biological conditions and the physical requirements for in vitro experiments are checked, two aspects are described. Firstly we achieved the characterization of the electromagnetic fleld generated around the biological system (both equipments and cultures). Secondly the analysis of the Speciflc Absorption Rate (SAR) inside the biological medium was evaluated both numerically and experimentally. Initially,

A possible role for extra-cellular ATP in plant responses to high frequency, low amplitude electromagnetic field.

In parallel to evoking the accumulation of stress-related transcripts, exposure to low level 900 MHz EMF affected the levels of ATP, the main energy molecule of the cell. Its concentration dropped rapidly (27% after 30 min) in response to EMF exposure, along with a 18% decrease in the adenylate energy charge (AEC), a good marker of cell energy status. One could interpret this decrease in ATP and AEC in a classical way, i.e., as the result of an increase in cellular energy usage, but recent work brings exciting new insights in pointing out a signalling function for ATP, especially in the stress physiology context where it could trigger both reactive oxygen species and calcium movement (this latter being involved in plant responses to EMF exposure). In this addendum, we discuss our results within this new perspective for ATP function.

Stochastic EMC/EMI Experiments Optimization Using Resampling Techniques

Recent studies have shown high interest in statistical methods dedicated to the prediction of the maximum confidence levels in simulations and measurements for risk assessment in electromagnetic compatibility. In particular, it has been shown that one of the main issues remains the access to a number of samples allowing the assessment of the risks in regards to test setup random variables. In this paper, it is argued that a real-time bootstrapping module enables to optimize the number of experiments while estimating the maximum confidence levels of the accessible samples. An efficient technique is presented to substitute the full experimental requirements to a simple and low time-consuming mathematical algorithm. The benefits expected of this method are illustrated throughout experimental shielding effectiveness power measurements. Based upon an optimized statistical approach, the first statistical moments (e.g., mean and standard deviation) of power received inside a cabinet are provided jointly with an accurate assessment of powers quantiles, leading to a better evaluation of extreme values.

Evaluation of the impact of proximity effect in the calculation of the internal impedance of cylindrical conductors

In this paper we discuss how the inclusion of proximity effect influences the evaluation of the internal impedances of cylindrical conductors. After recalling the classical analytical formulation used for calculating internal impedance, we use a Finite Element Method (FEM) code, in order to take into account the proximity effect. We show that in a low voltage cable, at frequency higher than the industrial ones, and particularly above the kilohertz range, the impact of proximity effect is rather relevant and cannot be neglected when dealing with EMC issues related to cable networks.

Unscented transform and stochastic collocation methods for stochastic electromagnetic compatibility

This paper deals with the current growing interest concerning the use of stochastic techniques for electromagnetic compatability (EMC) issues. Various methods allow to face this problem: obviously, we may focus on the Monte Carlo (MC) formalism but other techniques have been implemented more recently (the unscented transform, UT, or stochastic collocation, SC, for instance). The aim of this work is to solve a stochastic electromagnetic compatibility problem (transmission line) with the UT and SC techniques and to face them with the reference MC results.

Stochastic approaches for ElectroMagnetic Compatibility: A paradigm from complex reverberating enclosures

The aim of this paper is to enforce stochastic techniques in a classical ElectroMagnetic Compatibility (EMC) issue. An experimental setup has been developed ex nihilo to model it. First, a quick glance over the physical context will give precisions about the objectives of this work. Then, the statistical developments are derived both from classical (but costly) Monte Carlo (MC) technique and other advanced stochastic methods. Finally, the presented results will lay emphasis on part of the accuracy, limits and abilities of the developed formalisms to improve the physical understanding of applied EMC issues.