This paper mainly introduces the principles of a type of circuit for measuring frequency & duty cycle of low-frequency signals, and its applications in neuron-threshold stimulator. The circuit has the advantages of simple structure and accurate measurement.
Brain ; physiology ; Electrophysiology ; Equipment Design ; Humans ; Neurons ; physiology ; Physical Stimulation ; instrumentation ; Signal Processing, Computer-Assisted ; instrumentation

PURPOSE: The association between tenaculum application to the cervix just before embryo transfer and lower pregnancy rate has been reported. However, studies on the use of tenaculum in intrauterine insemination (IUI) cycles are not available. This study attempted to investigate whether the use of tenaculum affects the clinical outcomes of IUI. MATERIALS AND METHODS: Two hundred and thirty three CC/hMG/IUI cycles of one hundred and forty three couples were recruited at Seoul National University Hospital from October 2006 to December 2008. Mock insemination and IUI with or without tenaculum application to the cervix were also performed, and clinical pregnancy rate was compared. RESULTS: The incidence of difficult mock insemination at the beginning of cycle was higher in the tenaculum use group (p < 0.001). No significant statistical difference in the clinical pregnancy rate was observed between the groups with or without tenaculum application (12.1% vs. 18.5%; p = 0.175), which was not influenced by the difficulty of mock insemination. CONCLUSION: The use of tenaculum during IUI may not affect the pregnancy outcome. Our results need to be confirmed by a prospective study in a larger population.
Adult ; Cervix Uteri/*physiopathology ; Female ; Hormones/blood ; Humans ; Incidence ; Infertility, Female/physiopathology/*therapy ; Insemination, Artificial, Homologous/*instrumentation ; Male ; Ovary/physiology ; Ovulation Induction ; Physical Stimulation/instrumentation ; Pregnancy ; Pregnancy Outcome ; Pregnancy Rate ; Treatment Outcome ; Uterine Contraction/*physiology