deletions | additions       diff --git a/Material_methods.tex b/Material_methods.tex  index 0d2a111..f51f6c5 100644  --- a/Material_methods.tex  +++ b/Material_methods.tex 
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The magnetic field was induced by a 5x5x5 cm$^3$ N48 NdFeB magnet (model BY0Y0Y0, K\&J Magnetics, Pipersville, PA, USA). The magnet was placed 1 cm away from the medium, without any contact, and fixed to a second independent support. The magnetic field intensity ranged from 200 to 300 mT at the medium location, as measured by a gaussmeter (Model GM2, AlphaLab, Salt Lake City, UT, USA).   Main tested sample was a 4x8x8 cm$^3$ water-based tissue-mimicking phantom made with 5\% polyvinyl alcohol (PVA), 0.1 \% graphite powder and 5\% salt, giving an electrical conductivity of 5 S/m. Three freezing/thawing cycles were applied to stiffen the material \cite{fromageau2007estimation}. The graphite powder (product \#282863, Sigma-Aldrich, Saint-Louis, MO, USA) was made of submillimeter particles, which presented a speckle pattern on ultrasound images. The sample was placed in a rigid plastic box of 2 mm thick layers with an opening on a side to introduce the ultrasound probe. The rigid box simulated a solid interface such as a skull. It was also used to ensure that any observed movement was not due to surrounding displacement of air. We also Alternatively, we  used a similar phantom made of 5\% polyvinyl alcohol (PVA), 0.1 \% graphite powder and 0.9\% salt, giving an electrical conductivity of 1.8 S/m. A  biological tissue sample. sample was also tested.  This tissue was an approximately 3x5x5 cm$^3$ chicken breast sample, placed in the plastic box previously described,was  immersed in saline water (0.9 \% NaCl, giving an electrical conductivity of 1.8 S/m) at 20$^o$C and degassed during two hours. Each sample was observed with a 5 MHz ultrasonic probe made of 128 elements (ATL L7-4, Philips, Amsterdam, Netherlands) coupled to a Verasonics scanner (Verasonics V-1, Redmond, WA, USA). The probe was in contact with the sample with an ultrasound coupling gel but was fixed on a third independent support. It was used in ultrafast mode \cite{bercoff2004supersonic}, to acquire 1000 frames per second using plane waves and Stolt's fk migration algorithm \cite{garcia2013stolt}. The Z component of the displacement in the sample was observed by performing cross-correlations between radiofrequency images with a speckle-tracking technique \cite{montagnon2012real}. The TMS electrical current burst was triggered 10 ms after the beginning of the ultrasound frame acquisition, and the time $t$ = 0 ms was defined as the trigger emission.