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Three bilayer muscles [polypyrrole-paraphenolsulfonic acid/polypyrrole-dodecylbenzensulfonic acid (PPy-HpPS/PPy-DBS) asymmetric bilayer, PPy-HpPS/tape, and PPy-DBS/tape] were characterized during potential cycling in NaPF6 aqueous solutions. In parallel, the angular displacement of the muscle was video-recorded. The dynamo-voltammetric (angle-potential) and coulo-dynamic (charge-potential) results give the reaction-driven ionic exchanges in each PPy film. Electrochemical reactions drive the exchange of anions from the PPy-HpPS layer and cations from the PPy-DBS layer. This means that both layers from the asymmetric bilayer follow complementary volume changes (swelling/shrinking or shrinking/swelling), owing to complementary ionic exchanges (entrance/expulsion) driven by the bilayer oxidation or reduction. The result is a cooperative actuation; the bending amplitude described by the asymmetric bilayer muscle is one order of magnitude larger than those attained from each of the conducting polymer/tape muscles. The cooperative actuation almost eliminates creeping effects. A large dynamical hysteresis persists, which can be attributed to an irreversible reaction of the organic acid components at high overpotentials.

Thick films of the polypyrrole-para-phenolsulfonic acid (PPy-HpPS) blend were electrogenerated on stainless steel plates. The self-supported films, once peeled off from the metal, were electrochemically characterized in aqueous solutions of NaCl and NaPF 6 . The Na, Cl, P, S and F content of films, after attaining a different oxidation state, were determined by EDX. The bending movements of the bilayer (PPy-HpPS)/tape artificial muscle were video recorded during potential sweeps in both solutions allowing the translation of the prevalent ionic exchanges driven by the biomimetic reactions into macroscopic movements. Ionic exchanges between the film and the solution, biomimetic structural processes in the film, driving prevalent electrochemical reactions and film compositions related to each of the different structural potential domains defined by coulovoltammetric results were clarified. In NaPF 6 solutions a prevalent exchange of anions exists: the film swells by oxidation and shrinks by reduction. In NaCl solutions prevailing exchange of cations or anions occurs in different potential ranges. Reactions related to the HpPS content play important roles at the more cathodic and more anodic overpotentials. The described methodology could be translated to biological reactions including reactive biopolymers.

This case report describes successful pregnancies after vitrification of human day-7 blastocysts. A total of 16 day-7 blastocysts were vitrified and warmed. All 16 blastocysts survived after warming and were transferred to 11 patients. Six of the women (55%) became clinically pregnant and the implantation rate was 44% (7/16). Among these women, one woman delivered a healthy baby, two pregnancies ended in miscarriage, and three pregnancies are ongoing at 10, 29 and 34 weeks of gestation. This is the first report of successful pregnancies after vitrification of human day-7 blastocysts.

Purpose: To evaluate the effect of the size of zona pellucida opening by laser assisted hatching for frozen cleaved embryo that were thawed after both fresh and frozen cleaved embryo transfer cycles failed and were cultured to blastocyst after thawing in patients with multiple implantation failures., Materials and Methods: Of 101 consecutive procedures (October 2003 to June 2006), 30 patients declined to perform assisted hatching and were selected as control group, 40 patients had 40 microm opening of the zona (October 2003 to January 2005), 31 patients had 50% of the zona opening (February 2005 to June 2006)., Results: The pregnancy, implantation and delivery rates were significantly higher in 50% opening group (74%, 52% and 65%) compared to control group (17%, 10% and 13%; P < 0.01) and 40 microm opening group (43%, 27% and 38%; P < 0.04)., Conclusions: The size of the zona pellucida opening may affect the outcome of frozen cleaved embryo transfer.

The objective of this study was to investigate whether a change in assisted hatching technique from partial opening to total removal of the zona pellucida improved the outcome of vitrified blastocyst transfer. This was a preliminary observational study conducted from November 2003 to April 2006. Partial opening using acid Tyrode's solution was performed in 45 cycles, while total removal using a laser and mechanical pipetting was performed in 57 cycles. The clinical pregnancy, implantation, and delivery rates were higher in the total removal group than in the partial opening group (67% versus 42%, P < 0.02; 55% versus 30%, P < 0.01; 56% versus 36%, P < 0.04, respectively). These results suggest that total removal of the zona pellucida is associated with higher pregnancy, implantation and delivery rates compared with partial opening for vitrified blastocyst transfer.

The streaklines of unsteady separation on two kinds of pitching airfoils, the NACA65-0910 and a blunt trailing edge airfoil, were studied by dye flow visualization and by the Schlieren method. The latter visualized the discrete vortices shed from the leading edge. The results of these visualization studies allow a comparison between the dynamic behavior of the streakline of unsteady separation and that of the discrete vortices shed from the leading edge. The influence of the airfoil configuration on the flow characteristics was also examined. Furthermore, the scale of a discrete vortex forming the recirculation region was investigated. The non-dimensional pitching rate was k = 0.377, the angle of attack alpha(m) = 16 degrees and the pitching amplitude was fixed to A = +/-6 degrees for Re = 4.0 x 10(3) in this experiment.