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ObjectiveIn search of an ideal method of assisted hatching (AH), we compared the effects of conventional micropipette-AH and laser-AH on the blastocyst formation rate (BFR) and blastocyst cell numbers.MethodsFour- to five-week-old ICR female mice were paired with male mice after superovulation using Pregnant mare's serum gonadotropin (PMSG) and hCG. The two-cell embryos were flushed from the oviducts of female mice. The retrieved two-cell embryos underwent one of five AH procedures: single mechanical assisted hatching (sMAH); cross mechanical assisted hatching (cMAH); single laser assisted hatching (sLAH); quarter laser assisted hatching (qLAH); and quarter laser zona thinning assisted hatching (qLZT-AH). After 72 hours incubation, double immunofluorescence staining was performed.ResultsFollowing a 72 hours incubation, a higher hatching BFR was observed in the control, sMAH, cMAH, and sLAH groups, compared to those in the qLAH and qLZT-AH groups (p<0.05). The hatched BFR was significantly higher in the qLAH and qLZT-AH groups than in the others (p<0.05 for each group). The inner cell mass (ICM) was higher in the control and sMAH group (p<0.05). The trophectoderm cell number was higher in the cMAH and qLAH groups (p<0.05).ConclusionOur results showed that the hatched BFR was higher in groups exposed the the qLAH and qLZT-AH methods compared to groups exposed to other AH methods. In the qLAH group, although the total cell number was significantly higher than in controls, the ICM ratio was significantly lower in than controls.

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Seven experimental poly(ethylene terephthalate) (PET) fibers were spun and then drawn under different processing conditions (i.e., spinning speed and draw ratio) in such a way that the fibers possessed different long periods but retained the same crystal structure. Wide angle X-ray diffraction, small angle X-ray scattering, loss modulus, initial modulus, and taut tie molecules measurements were used to characterize the fine structure and the physical property of the fibers. The influence of the fine structure on the extensional fatigue behavior of the PET fibers was studied by subjecting them to 120 -180 rpm at a repeated extension at 10 4 -10 6 cycles. In order to detect the molecular motion of PET with the extensional fatigue, we carried out differential scanning calorimetry, X-ray diffraction, density, and thermoluminescence (TL) experiments. The high temperature TL (above room temperature) intensity decreased with a 10 4 cycle extension but increased with a 10 5 cycle extension. The extent of change in the TL intensity was found to be a function of the long period and loss modulus.