RESUMO
We report the theoretical prediction of single and paired electron self-trapping in Ge(2)Se(3). In finite atomic cluster, density functional calculations, we show that excess single electrons in Ge(2)Se(3) are strongly localized around single germanium dimers. We also find that two electrons prefer to trap around the same germanium dimer, rupturing a neighboring Ge-Se bond. Localization is less robust in periodic, density functional calculations. While paired electron self-trapping is present, as shown by wavefunction localization around a distorted Ge-Ge dimer, single-electron trapping is not. This discrepancy appears to depend only on the boundary conditions and not on the exchange-correlation potential or basis set. For single- and paired-electron trapping, we report the adiabatic barriers to motion and we estimate hopping rates and freeze-in temperatures. For the single trapped electron, we also predict the (73)Ge and (77)Se hyperfine coupling constants.
RESUMO
From March 1994 to February 1996, 28 infertile couples participated in the oocyte donation program in 33 treatment cycles at the Southeastern Fertility Institute. Of the 31 cycles with embryo transfer, 15 cycles (48.4 percent) resulted in a clinical pregnancy with fetal heart beat by ultrasound. The spontaneous first trimester abortion rate was 3/15 (20 percent), multiple pregnancy rate 3/15 (20 percent), live birth rate 11/15 (73.3 percent) and delivery rate 12/15 (80 percent). It is recommended that oocyte donation procedure is a highly successful treatment option for women with ovarian failure or repeated unsuccessful trials of assisted reproductive technologies.