Overall Blastocyst Quality, Trophectoderm Grade, and Inner Cell Mass Grade Predict Pregnancy Outcome in Euploid Blastocyst Transfer Cycles

Background： Despite recent advances that have improved the pregnancy success rates that can be achieved via in vitro fertilization （IVF） therapy, it is not yet clear which blastocyst morphological paralneters best predict the outcomes of single blastocyst transfer. In addition. most of the previous studies did not exclude the effect of embryo aneuploidy on blastocysts transfer. Thus, the present study investigated the predictive value of various parameters on the pregnancy outcomes achieved via the transfer of frozcn euploid blastocysts. Methods： The study retrospectively analyzed 914 single euploid blastocyst transfer cycles that were performed at the Peking U laivcrsity Third Hospital Reproductive Medical Center between June 2011 and May 2016. The expansion, trophectoderm （TE）. and inner cell mass （ICM） quality of the blastocysts were assessed based on blastocyst parameters, and used to differentiate between ＂excellent＂, ＂good＂, ＂average＂, and ＂poor＂-quality embryos. The relationship between these embryo grades and the achieved pregnancy outcomes was then analyzed via the Chi-square and logistic regression tests. Results： For embryo grades of excellent, good, average and poor, the clinical pregnancy rates were 65.0%. 50.3%, 50.3% and 33.3%. respectively; and the live-birth rates were 50.0%, 49.7%, 42.3% and 25.0%, respectively. Both the clinical pregnancy ratc （x2= 21.28. P = 0.001） and live-birth rate （x2 = 13.50, P 〈 0.001） increased with the overall blastocyst grade. Both rates were significanlly higher after the transfer era blastocyst that exhibited either an A-grade or B-grade TE, and similarly, an A-grade ICM. than after the transfer el a blastocyst that exhibited a C-grade TE and/or ICM. The degree of blastocysl expansion had no apparent effect on the clinical pregnancy or live-birth rate. All odds ratio were adjusted for patient age, body mass index, length （years） of infertility history, and infertility type. Conclusions： A higher overall euploid blastocyst quality is shown to correlate most strongly with optimal pregnancy outcomes. The study thus supports the use of the described TE and ICM morphological grades to augment current embryo selection criteria.

Kinetic modeling on hot metal desulfurization with mechanical stirring

A kinetic model on hot metal desulfurization with mechanical stirring was established using FactSage Macro Processing.The sulfur diffusion in the molten steel and reactions at the interface between the molten steel and the desulfurizer particle were considered.Calculated results agreed well with experimental results,indicating that the model can be used to predict the desulfurization rate and cost with various temperatures,chemical compositions,rotation speeds,and desulfurizer additions.The higher impeller rotation speed from 80 to 120 r/min,higher temperature from 1573 to 1673 K,smaller particle size from 2.5 to 1.5μm,and more desulfurizer addition from 0.35 to 0.64 kg/t were suggested to improve the desulfurization rate.Moreover,to synthetically increase the desulfurization efficiency and lower the cost,contours of S content and cost during the desulfurization process with various desulfurizer additions and time were calculated.Based on industrial cost data analysis of the added desulfurizer,the refractory erosion,and electric power consumption,the total cost of the hot metal desulfurization with time step(Δt)was fitted as Cost_(total)=0.066+1.58×10^(−7)·Δt.The less desulfurizer addition and longer desulfurization time contributed to lowering the cost,while more desulfurizer addition was conducive to improving the desulfurization efficiency.