Objective
The present study aimed to determine the relationship between the serum hepcidin level and disease activity in patients with rheumatoid arthritis (RA).
Methods
This study was conducted on 80 patients with RA (36 cases with anemia of chronic disease [ACD] and 44 patients without ACD). Disease activity was measured by the 28-joint Disease Activity Score based on the erythrocyte sedimentation rate (DAS28-ESR). According to the DAS28-ESR score, 52 and 28 cases were categorized as inactive to moderately active RA (DAS28-ESR≤5.1) and highly active RA (DAS28-ESR>5.1), respectively. In addition, the serum hepcidin level was evaluated in all patients to determine its correlation with the DAS28-ESR score.
Results
There was no significant difference between the RA with ACD and RA without ACD groups in terms of the median (interquartile range) hepcidin level (1207 [985.2] vs. 923.8 [677.3] ng/mL; P=0.57). Likewise, no significant difference was observed between the active RA and inactive to moderately active RA groups in this regard (1131.8 [991.3] vs. 1090.9 [631.4] ng/mL; P=0.53).
Conclusion
Hepcidin has no association with disease activity in RA. Therefore, it is not necessary to measure hepcidin to determine the RA activity.
In this study, a single‐layer balanced wideband phase shifter with a wide phase shift range of 45°–315° and acceptable common‐mode (CM) suppression is proposed. The main branch has a simple ladder‐like structure and the reference branch utilises a coupling structure. The main branch electrical length is constant for any desired differential‐mode (DM) phase shift. Assuming a specific return loss (e.g. 16, 20, and 25 dB), the phase shifter is carefully analysed and a design procedure is given leading to an ultra‐low phase error design. Then by making a trade‐off between the CM and DM bandwidths at the cost of higher phase error, more design solutions for the phase shifter are given. To validate both the proposed structure as well as its design procedure, a balanced wideband phase shifter with the DM phase shift of 180°±4.2° (1.851–4.017 GHz) and the CM suppression of better than 15 dB (1.81–4 GHz) is fabricated, resulting in 73.82 and 75.25% fractional bandwidth, respectively. The fabricated balanced phase shifter has a return loss of ||S11dd<−14.87thinmathspacedB and insertion loss of ||S21dd>−0.95thinmathspacedB. The synthesised, simulated, and measured results are in good agreement with each other.
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