Frozen embryo transfer: Endometrial preparation by letrozole versus hormone replacement cycle: A randomized clinical trial

Background: The endometrial preparation with stimulating natural cycles for frozen embryo transfer (FET) have benefits like lower cost and ease of use. Objective: Comparing the clinical outcome of letrozole versus hormone replacement (HR) for endometrial preparation in women with normal menstrual cycles for FET in artificial reproduction techniques. Materials and Methods: A total of 167 participants who had frozen embryos and regular ovulatory cycles were randomly divided into two groups for endometrial preparation. One group (82 women) was stimulated with letrozole 5mg/day and the other group (85 women) was hormonally stimulated by oral estradiol valerate (2 mg three times a day). All participants were followed serially by ultrasonography. Any patient who did not reach optimal endometrial thickness was excluded from the study. Implantation, biochemical and clinical pregnancy and abortion rate were reported. Results: There was no significant difference in the mean age, duration, and primary or secondary infertility, cause of the infertility, number, and quality of transferred embryos between the groups. The mean estradiol level on the day of transfer was 643 ± 217 in the HR group and 547 ± 212 in the letrozole group (P = 0.01), which was significantly different. The clinical pregnancy rate was 38.7 in the letrozole group, higher than the HR group (25.3) but not significantly different (P=0.06). Conclusion: For endometrial preparation in women with a normal cycle, letrozole yields higher pregnancy rate although it is not significant; due to its cost, ease in use, and lower side effects, letrozole is a good choice. Key words: Letrozole, Hormone replacement, Endometrial, Preparation, Frozen, Embryo

Determination of suitable poplar clones in short rotation system in Chamestan

For determining of suitable poplar clones for utilizing in cellulose  industries  on the basis of maximum wood  production in hectar ,15 clones of Populus deltoides, P.euramericana and P.nigra were studied in three exploitaion period (2,3 and 4 years) in chamestan of Mazandran province. In order to homogenize the material, all the shoots were cut at the bottom after the first growth year. At the end of each exploitation period, all stems and shoots were cut and weighted two times; 1) wet wood product and 2) dry biomass after six months of drying in the open air. Some parameters such as survival, number  of total coppice stems per collar, number of shoots over 2 m height, mean diameter and mean height of shoots over 2 m height, diameter and height of the highest  stems and resistance to pests and diseases were studied and compared at the end of the project. Results were analized on the basis of randomized complete block design. Results showed that : a) In 2 years short rotation system, P.d. 69/55, P.e. triplo and P.d. 73/51 produced the highest amount of dry biomass of 20.05, 17.52  and 17.19 ton/ha/year,respectively. b) In 3 years short rotation system, P.d.77/51, P.e. triplo and P.d. 69/55 produced the highest amount of dry biomass of 16.70, 15.75 and 14.73 ton/ha/year, respectively. c) In 4 years short rotation system, P.d. 69/55, P.d. 77/51 and P.e. triplo produced the highest amount of dry biomass of 19.00, 17.77 and 16.96 ton/ha/year, respectively. The diffrences between dry biomass production of poplar clones in each rotation system were significant