In vitro fertilization (IVF) is a feasible way to utilize sex-sorted sperm to produce offspring of a predetermined sex in the livestock industry. The objective of the present study was to examine the effects of various factors on bovine IVF and to systematically improve the efficiency of IVF production using sex-sorted sperm. Both bulls and sorting contributed to the variability among differential development rates of embryos fertilized by sexed sperm. Increased sorting pressures (275.8 to 344.75 kPa) did not have a significant effect on the in vitro fertility of the sorted sperm; neither did an extended period of 9 to 14 h from semen collection to sorting. As few as 600 sorted sperm were used to fertilize an oocyte, resulting in blastocyst development of 33.2%. Postwarming of vitrified sexed IVF embryos resulted in high morphological survival (96.3%) and hatching (84.4%) rates, similar to those fertilized by nonsexed sperm (93.1 and 80.6%, respectively). A 40.9% pregnancy rate was established following the transfer of 3,627 vitrified, sexed embryos into synchronized recipients. This was not different from the rates with nonsexed IVF (41.9%, n = 481), or in vivo-produced (53.1%, n = 192) embryos. Of 458 calves born, 442 (96.5%) were female and 99.6% appeared normal. These technologies (sperm sexing-IVF-vitrification-embryo transfer) provide farmers, as well as the livestock industry, with a valuable option for herd expansion and heifer replacement programs. In summary, calves were produced using embryos fertilized by sex-sorted sperm in vitro and cryopreserved by rapid cooling vitrification.

The electrothermal (electrocaloric and pyroelectric) properties of ferroelectric thin films have many applications in active solid-state cooling and infrared sensing devices. It has been shown experimentally that some thin-film ferroelectrics can produce much larger electrothermal responses than their bulk counterparts. In this work, the electrothermal properties of bulk polar dielectric (ferroelectric and incipient ferroelectric) materials and thin films have been computed using a thermodynamic methodology and the effects of electrical, thermal and mechanical boundary conditions have been illustrated. In particular, the sensitivity of pyroelectric and electrocaloric response to bias and driving fields, lateral clamping and misfit strain, thermal stresses and composition have been demonstrated. The computations show that the electrothermal behavior of ferroelectric materials for practical cooling devices depends on a complex interplay of several related sets of physical phenomena. These include the nature of the ferroelectric transition, the particular dependence of the equilibrium and transport properties on electric field and mechanical boundary constraints, and the orientation and thermal expansion coefficients of the thin film and substrate materials. The combined results provide insights concerning how the composition and orientation of the thin film material, the choice of substrate, the deposition/annealing temperature, and the electrode configuration can be used to optimize the electrothermal properties for particular applications.

Author(s)Kesim, M. T.; Zhang, J.; Trolier-McKinstry, S.; Mantese, J. V.;Whatmore, Roger W.; Alpay, S. P. Ferroelectric lead zirconate titanate [Pb(Zr x Ti 1-x O) 3 , (PZT x:1-x)] has received considerable interest for applications related to uncooled infrared devices due to its large pyroelectric figures of merit near room temperature, and the fact that such devices are inherently ac coupled, allowing for simplified image post processing. For ferroelectric films made by industry-standard deposition techniques, stresses develop in the PZT layer upon cooling from the processing/growth temperature due to thermal mismatch between the film and the substrate. In this study, we use a non-linear thermodynamic model to investigate the pyroelectric properties of polycrystalline PZT thin films for five different compositions (PZT 40:60, PZT 30:70, PZT 20:80, PZT 10:90, PZT 0:100) on silicon as a function of processing temperature (25-800 C). It is shown that the in-plane thermal stresses in PZT thin films alter the out-of-plane polarization and the ferroelectric phase transformation temperature, with profound effect on the pyroelectric properties. PZT 30:70 is found to have the largest pyroelectric coefficient (0.042 lC cm À2 C Publication date 2013 Original citation À1, comparable to bulk values) at a growth temperature of 550 C; typical to what is currently used for many deposition processes. Our results indicate that it is possible to optimize the pyroelectric response of PZT thin films by adjusting the Ti composition and the processing temperature, thereby, enabling the tailoring of material properties for optimization relative to a specific deposition process. V C 2013 AIP Publishing LLC. [http://dx

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