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Objective Repeated implantation failure (RIF) is a major challenge in reproductive medicine. On the other hand, there has not yet been established a confirmed outcome regarding the usage of platelet-rich plasma (PRP) in women undergoing intracytoplasmic injection (ICSI) or in-vitro fertilization (IVF); hence, the objective of this study was to evaluate the effect of the intrauterine infusion of PRP on pregnancy outcomes in women undergoing ICSI. Methods In this prospective double-blind clinical trial, 100 women with at least two previous unexplained RIF, who were candidates for frozen-thawed embryo transfer, were allocated into two groups. One subgroup of patients was treated by intrauterine infusion of PRP (0.5CC, contained platelet 4-5 times more than a peripheral blood sample, which was performed 48 hours before blastocyst transfer) and the other subgroup was treated by intrauterine catheterization only. We compared the implantation rates between the two groups. Results The pregnancy rate was 20% in the intervention subgroup, while in the control subgroup it was 13.33%; therefore, there was a significant statistical difference between the two groups. Conclusions According to this paper, PRP could be successful in improving the pregnancy outcome in RIF patients, and we highly recommend other studies with larger samples to confirm the PRP therapy efficacy in RIF patients.

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This paper discusses the design of a cascade con-deflection. In [1], [8] and [12] a combination of nonlintroller for active suspension systems, to improve ride quality. ear and adaptive control is proposed to counteract acIn order to do this, in the main loop, a model reference adap-tuator nonlinearity and uncertainties. In [11] model refertive controller is designed to attenuate disturbances due to * * rough roads. An internal loop provides the required control .en enadaptverc l is introduce. 'whic hasreltivei force for the main controller. The closed loop system has de-provement in vertical acceleration. However this controller sired robust stability and performance in the presence of unis not robust and is highly dependent on initial condition of certainty due to time varying parameters and nonlinear dy-parameters. The other drawback is that only local stability namics of the actuator. The simulation results show the effecis guaranteed by using this controller. This problem is tiveness of the suggested method in increasing ride comfort and solved in [6] using variable structure (VS) MRAC. Howsafety while constrains of suspension system maneuverability is ever in the latter two papers, wheel dynamics is ignored and also satisfiled.control strategy has solution only when the matching condiKey Words-Suspension System, Electro-Hydraulic Ac-tions are satisfied tuator, Model Reference Adaptive Control, SPR LyapunovThe present paper proposes a cascade controller; a Approach, Cascade Control, Disturbance Attenuation.MRAC based on Lyapunov theory for the two degree of freedom active suspension quarter car model in the main loop, which is designed to attenuate road disturbances. To I. INTRODUCTION demonstrate robustness of the closed loop structure, a proportional controller forces the actuator to track desired con-A good suspension system is expected to improve ride trol effort generated by the main loop. This strategy has the quality by decreasing the transferred force to the passenger. desired nominal response. Besides, robust stability and perRoad handling especially in high speeds is another ex-formance is achieved in the presence of nonlinear dynamics pected specification of such a systems. In order to decrease and time varying parameters. As measuring signals are used body acceleration, the suspension system spring should solely, there is no need to design observer. have unlimited displacements. Because of restriction in the spring movement, there should be a trade off between these II. SYSTEM DYNAMICS two objectives.Generally there are 3 types of suspension systems; pasIn Fig. 1, a quarter car linear model of the system is sive, semi active and active suspension. Suspension sys-shown. The car body is modeled by a sprung mass, MS tem's task is to change the length of the spring and shock absorber proportional to dumps, in order to decrease the s oent Bya dme and s with coeffi transferred force to passenger. The magnitude of this force cient B, and K. respectively. The wheel is also modeled is different in variou...

The best time of endometrial receptivity is the missing part of the implantation puzzle in patients with recurrent in vitro fertilization (IVF) failure. There are various treatment plans and strategies to meet the best endometrial timing for implantation. However, the lack of synchronization of the good-quality embryo with the patient's individual “window of implantation” is the hypothesis for most IVF failures so far. Sequential embryo transfer (ET) theoretically extends the availability time of embryos on the window of implantation. The study aimed to evaluate the improvement of pregnancy rate in sequential (two-step) frozen-thawed embryo transfer (FET) on day 3/day 5 in individuals who suffer from repeated IVF failures. This randomized controlled trial study was done in a university-affiliated infertility center for women with repeated consecutive IVF failures. Two hundred women aged 20–39 years who met our inclusion criteria were included in the study between January 2020 and September 2021. Participants were allocated with a 1:1 ratio to either sequential (two-step) ET on day 3/day 5 (study group, n=100) and conventional day 5 FET (n=100, control group). The frozen-thawed embryos were transferred to hormone replacement therapy-prepared endometrium in both groups. The primary outcomes were clinical pregnancy and implantation rates. The secondary outcomes were early pregnancy loss and multiple pregnancies. The demographic and clinical characteristics of the two groups were comparable. Clinical pregnancy rates were significantly higher in the sequential (two-step) FET group (40%) compared to the day 5 group (19%) (P<0.001). The sequential transfer of frozen-thawed embryos on day 3/day 5 was more effective than regular day 5 for patients suffering from repeated IVF failure.

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