Thermoacoustic tomography arising in brain imaging

We study the mathematical model of thermoacoustic and photoacoustic tomography when the sound speed has a jump across a smooth surface. This models the change of the sound speed in the skull when trying to image the human brain. We derive an explicit inversion formula in the form of a convergent Neumann series under the assumptions that all singularities from the support of the source reach the boundary

Evaluation of cytotoxic compounds in different organs of the sea bream <i>Sarpa salpa</i> as related to phytoplankton consumption: an in vitro study in human liver cell lines HepG2 and WRL68

The present study was aimed to assess the cytotoxic effects of not-yet identified compounds present in organ extracts of Sarpa salpa, collected in autumn, the period with a peak in health problems. In addition, we studied the cytotoxicity of extracts of epiphytes found in the stomach content of S. salpa collected in summer and of epiphytes collected from the sea in the Sfax area at the end of spring. We tested these fractions in two human hepatic cell lines: HepG2 and WRL68. We observed a significant loss of viable cells when HepG2 cells were exposed for 72 h to acetone extracts of livers of S. salpa at a concentration of 2.5 mg/ml protein. Proteins extracted from brain or muscle did not significantly induce cell death at the studied concentrations (a parts per thousand currency sign10 mg/ml). There was a significant loss of viable cells when treated with liver extract of S. salpa dissolved in DMSO. Extracts of epiphytes collected in late spring showed a cytotoxic effect in a concentration-dependent manner. Moreover, we observed a significantly decreased cell viability of HepG2 at a dilution (1/40) of epiphyte extracts from stomach contents of two fish we had collected. The cytotoxic effect of the observed epiphyte extracts confirms the transfer of toxins originating from toxic dinoflagellates which live in epiphyte on the Posidonia oceanica leaves to fish organs by grazing. Hence, the liver of this fish can cause a threat to human health and consumption should for this reason be dissuaded

Enzymatic antioxidant responses and mineral status in roots and leaves of olive plants subjected to fluoride stress

International audienceFluoride (F) as one of the most toxic pollutants affecting the environment severely restricted plant growth and development. The Fluoride toxicity was studied in young olive plants (Olea europaea L. cv Chemlali), which were irrigated for 5 months with increasing NaF concentration: 0 (control), 20, 40, and 80 mM NaF. The NaF application resulted in an increase of the F content in plant tissues with a higher level in roots compared to leaves. Olive plants treated with 20 or 40 mM NaF maintained their mineral status and activated their antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase). In fact, lipid peroxidation and electrolyte leakage were not affected in the plant leaves. However, olive plants treated with 80 mM NaF showed (i) the highest reduction of antioxidant enzyme activities and mineral contents, and (ii) an increase of oxidative stress markers such as hydrogen peroxide, thiobarbituric acid reactive substances and electrolyte leakage in both roots and leaves. © 201