Search PubMed⌕ Search

Biomedical subjects

Michel Fournier

Publications and source records attributed to Michel Fournier.

56 records · Page 4Linked to original sources
PubMed2002

Response of the amphibian tadpole Xenopus laevis to atrazine during sexual differentiation of the ovary.

Xenopus laevis tadpoles (stage 56) were exposed to 21 microg/L atrazine under laboratory-controlled conditions in a static system. Following a 48-h exposure period at 21+/-0.5 degrees C during sexual differentiation, tadpoles were fixed, and the kidney-gonad complex was microdissected. Quantitative histological analysis revealed in atrazine-exposed ovaries a significant (p < 0.05) increase in frequency of secondary oogonia. Atresia, or oogonial resorption of both primary and secondary oogonia, also increased significantly (p < 0.05). The results suggest that these primary germ cells, which constitute the total number of germ cells in the ovary for the reproductive life of the organism, were reduced by 20% following a 48-h exposure period compared to 2% in controls.

Animals↗
PubMed1996

Electrochemical Properties and ESR Characterization of Mixed Valence alpha-[XMo(3)(-)(x)()V(x)()W(9)O(40)](n)()(-) Heteropolyanions with X = P(V) and Si(IV), x = 1, 2, or 3.

Electrochemical behavior of the alpha-[SiMo(3)(-)(x)()V(x)()W(9)O(40)]((4+)(x)()())(-) and alpha-[PMo(3)(-)(x)()V(x)()W(9)O(40)]((3+)(x)()())(-) anions with x = 1, 2, or 3 were studied. Electrochemical reduction of each compounds was consistent with its Mo/V ratio, reduction of vanadium and molybdenum atoms occurring in the +0.6 to -0.6 V potential range. The one-electron-reduced species were prepared by electrolysis and then characterized by ESR spectroscopy. The g and A values for V(4+)ions appeared to depend on the nature of the surrounding atoms (Mo(VI), W(VI), and V(V)). In solution at 330 K, the ESR spectrum of the protonated alpha-H[SiMoV(IV)VW(9)O(40)](6)(-) anion displayed 29 superhyperfine lines which were related to the partial localization of the electron on one vanadium nucleus. The ESR spectra at room temperature for the divanadium-substituted anions showed a strong anisotropy of the A tensor which would be related to the electron transfer along a preferential axis. An isolated V(4+) signal was not observed, even at 12 K, indicating that the electron is never firmly trapped on one single vanadium atom.

Journal Article↗