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This paper proposes a soft-switching (SS) active snubber cell for half-bridge (HB) DC–DC converters, which are utilized in hybrid vehicle battery charge applications. The proposed converter has an advantage over conventional HB DC–DC converters, which suffer from transformer leakage inductance issues. The new snubber cell performs SS operation using the energy stored in the leakage inductance. Thus, the leakage inductance, which creates troubles for HS DC–DC converters, is beneficial to the proposed converter. The proposed SS HB DC–DC converter is compared with the conventional HB DC–DC converter under 100 kHz and 110 W output power operating conditions. The efficiency of the proposed converter is 7.3% and 4.8% higher than the conventional HB converter at light and heavy loads, respectively. The proposed active snubber cell provides complete SS for the main and auxiliary semiconductor switches. The new snubber cell has a basic structure, low-cost, ease of application, and simple control features. [ABSTRACT FROM AUTHOR]

In this paper, a new single-stage high power factor (PF) isolated AC–DC topology is proposed. In this topology, two DC–DC converters are used, one as a power factor correction (PFC) cell and the other as a regulation (REG) cell. Also, two storage capacitors (SC) are used, one at the input for REG and the other in serial to output for direct power transfer (DPT). PFC cell transfers most power directly to outlet SC with flyback operation and the rest of the power to inlet SC with the simultaneous buck–boost operation. It also provides high PF with discontinuous current mode (DCM). REG cell is fed from inlet SC at low power, works as a power amplifier with DCM, transfers all power to the output provides a tight REG. The topology also provides a high duty cycle (D). Thus, low current stress and high efficiency are achieved with high D and high DPT. The steady-state analysis of the new topology is presented. This analysis is verified by a prototype with output voltage 120 V, output power 120 W, and switching frequency 100 kHz, in 85 VRMS–265 VRMS line voltage range. Finally, 51% maximum D, 96% DPT, and 94% efficiency are achieved. [ABSTRACT FROM AUTHOR]

This paper introduces a novel modular active snubber cell for isolated half-bridge converters with ease of control. The novel snubber cell can achieved soft switching for all semiconductors at the proposed converter. The switches in the converter are derived simultaneously by the normal pulse-width modulation signals. The introduced snubber cell has a quite simple structure and ease of control. In this converter, the main switches turn on with zero current switching and turn off with zero voltage switching. Besides, there is no extra voltage stresses on the power elements. The proposed half-bridge DC–DC converter is analyzed in detail and its theoretical analysis is verified with a prototype having 50 A–25 V output values at 80 kHz frequency. [ABSTRACT FROM AUTHOR]

Purpose: Endometrial polyp is the commenest pathology among the structural uterine abnormalities. In this study we compared the IVF outcomes of patients who underwent hysteroscopic endometrial polyp excision with respect to the time interval between the polyp resection and the subsequent IVF cycle. Materials and methods: A total of 60 patients were divided into two groups according to the time interval between the hysteroscopic polyp resection and the start of the following IVF cycle. Of these, 29 patients had the IVF procedures <6 months after the polyp resection, whereas in 31 patients comprising the comparison group, IVF interventions were done ≥6 months after the resection. The IVF outcomes were compared. Results: Differences in the mean number of retrieved oocytes, metaphase II (MII) oocytes and transferred embryos, ratios of MII oocytes, and G1, G2 and G3 embryo rates were insignificant between the groups ( p > 0.05). The fertilization, implantation, and clinical pregnancy rates were also similar between the groups ( p > 0.05). Conclusion: IVF outcomes seem to be unrelated to the time interval between the hysteroscopic polyp resection and the initiation of the IVF; the success rates may not be superior if the treatment is started in the first few months postoperatively. [ABSTRACT FROM AUTHOR]

Aim: The present case report describes colon injury subsequent to uterine penetration which is associated with the use of an intrauterine device (IUD). Case: A 29-year-old multiparous woman, who presented with vague abdominal pain, had a TCu 380A inserted at her postpartum third month visit. The T-shaped segment of the IUD was found to be lodged within the lumen of a colon segment which was 60 cm far from the ileocecal valve. The vertical copper-bearing limb of the IUD extruded from the colon wall beyond the mesenteric edge and partially penetrated the fundal wall. After the affected colon segment was resected, an end-to-end anastomosis was made. Recovery period was uneventful. Discussion: The incidence of uterine penetration is affected by the IUD type, the timing of insertion related to pregnancy termination, the position of uterus, insertion technique, the experience of the operator and the follow-up period. The location of missing IUDs can be determined by ultrasonography, X-ray or computed tomography imaging. [ABSTRACT FROM AUTHOR]