RESUMEN
In this paper, two sector beam scanning approaches (BSAs) based on element position perturbations (EPPs) in the azimuth plane are introduced. In EPP-BSA, the elements' excitations are kept constant and the elements' positions in the direction normal to the array line are changed according to a predetermined EPP pattern. The magnitude and repetition rate of the selected EPP pattern determines the steering angle of the main beam. However, EPP-BSA results in a wide scanning range with a significant increase in the side lobe level (SLL). To mitigate this drawback, a reduction in the SLL of the array pattern is firstly performed using the single convolution/genetic algorithm (SC/GA) technique and then perturbing the elements' positions in the azimuth plane. This combination between SLL reduction and EPP-BSA (SLL/EPP-BSA) results in a smaller scanning range with a relatively constant half power beamwidth (HPBW) and a much lower SLL. In addition, keeping the synthesized excitation coefficients constant without adding progressive phase shifters facilitates the manufacturing process and reduces the cost of the feeding network. Furthermore, a planar antenna array thinning approach is proposed to realize the EPP-BSA. The results are realized using the computer simulation technology (CST) microwave studio software package, which provides users with an optimized modeling environment and results in realizable and realistic designs.
RESUMEN
OBJECTIVE: To synthesize the evidence on the most effective medications for the relief of intrauterine device (IUD) insertion-related pain. DESIGN: Systematic review and network meta-analysis of randomized controlled trials (RCTs). SETTING: Not applicable. PATIENT(S): Patients undergoing IUD insertion who received different medications for pain relief versus those who received placebo. INTERVENTION(S): Electronic search in the following bibliographic databases: Medline via PubMed, SCOPUS, Web of Science, Cochrane Central Register of Controlled Trials (CENTRAL), and ScienceDirect. MAIN OUTCOME MEASURE(S): Visual analog scale (VAS) pain score during tenaculum placement, IUD insertion, and 5 to 20 minutes after insertion, the score of easiness of insertion and the need for additional analgesics. RESULT(S): The present review included 38 RCTs (n = 6,314 patients). The network meta-analysis showed that lidocaine-prilocaine cream (genital mucosal application) statistically significantly reduced pain at tenaculum placement compared with placebo (mean difference -2.38; 95% confidence interval, -4.07 to -0.68). In the ranking probability order, lidocaine-prilocaine cream ranked the highest in reducing the pain at tenaculum placement, followed by lidocaine (paracervical). Similarly, lidocaine-prilocaine cream ranked as the highest treatment in pain reduction during IUD insertion, followed by lidocaine (paracervical). CONCLUSION(S): Lidocaine-prilocaine cream is the most effective medication that can be used for IUD insertion-related pain. Other medications are not effective.
