deletions | additions       diff --git a/Biological tissue.tex b/Biological tissue.tex  index 41350ad..f8f7434 100644  --- a/Biological tissue.tex  +++ b/Biological tissue.tex 
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The sample was then replaced by a similar phantom except that cellulose particles were used instead of graphite particles: thus, the phantom presented a weak optical absorption but a comparable speckle pattern. A black disk of variable diameter was painted on a surface of the phantom at the laser beam impact location, to control the absorption area. The amplitude of the induced shear waves versus black disk diameter in the second phantom is illustrated in Fig. \ref{Figure3}-(B). We observe a linear relationship between shear wave amplitude and black disk diameter, with a correlation coefficient of 0.9281. In both series of experiments (20 plus 23 measurements), we measured shear wave frequency of 500 $\pm$ 100 Hz.  The potential application of these results on a biological tissue was finally studied. The phantom was replaced by a chicken breast sample bought in the local grocery. Due to the absence of absorbing material like melanin or haemoglobin, the laser was diffused in a large area with a very small increase of temperature and could not induce elastic waves. Accordingly, a 5 mm diameter black disk was painted on the surface of the sample at the laser beam incident location. Displacements were harder to compute because of the sample inhomogeneities, which led to low quality speckle.  Displacement amplitude maps along Y axis and Z axis 0.8, 1.6, 2.4, 3.2 and 4.0 ms after laser emission in the biological tissue are illustrated in Figure \ref{Figure5}. Shear waves propagated at a velocity of 5.5$\pm$.5 m.s$^{-1}$. It corresponds to a shear modulus of 30$\pm$5 kPa, which is a typical value for a relaxed muscle tissue \cite{sarvazyan1998shear}. The pattern is moreover very similar presented similarities  to the onepresented  in Figure \ref{Figure2}, suggesting similar involved phenomena. We found, again, a shear wave frequency of 500 $\pm$ 50 Hz.