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A wideband circularly polarized patch antenna is presented in this article. The four‐port antenna is composed of circular patch loaded with four shorting pins and cross‐shaped slot. The realization of wideband benefits from the cooperation of three resonant modes. The lowest mode is due to the resonance of half‐wavelength cross‐shaped slot, while the higher two modes are TM11 mode and TM31 mode of the circular patch, in which the TM31 mode is excited by loading four shorting pins. The L‐shaped probes are utilized to establish the coupling feed mechanism for impedance matching in a wideband range. And the compensation of the radiation null in the broadside direction benefits from the variation of the electric field distribution caused by the shorting pins and the differential L‐shaped feed structure in TM31 mode. For the aim of implementing circularly polarized radiation in the proposed patch configuration, a phase quadrature feed network consisting of power dividers and phase shifters is designed and cooperated with this antenna. In order to verify the design concept, a prototype has been fabricated, assembled and measured. The measured results show that the relative bandwidth of VSWR <1.7 and AR <3 dB is 66.7%, ranging from 2 to 4 GHz. In addition, the measured LHCP gain >3 dBic within 2.01–3.84 GHz, and the fractional bandwidth is 61%. Moreover, the peak gain is 9.9 dBic. [ABSTRACT FROM AUTHOR]

In this article, a new general and effective design method of miniaturized quasi‐lumped‐element wideband filtering phase shifters for integrated RF front‐end is proposed, which is promising in both industrial and academic fields. This wideband filtering phase shifter is built by exploring the multiple different kinds of lumped resonators and arranging them in an easily realizable form with stable performance on the single‐layer substrate using widely accessible and low‐cost PCB processing. In our design, wideband magnitude and phase shift responses with the multiple transmission zeros and small phase deviation are numerically established and obtained. A generalized synthesis method along with theoretical analysis and synthesis curves is proposed to determine its circuit parameters exactly. To verify the proposed design concept and method, two wideband phase shifter prototypes with the different topologies and specifications are implemented and tested. Comparisons of measured and simulated results show good accordance and verify theoretical predictions. These prototypes exhibit attractive features with satisfactory wide bandwidth, high frequency selectivity, small phase deviation, deep and wide stopband, miniaturized size, as well as flexible design freedom, compared to other existing works. [ABSTRACT FROM AUTHOR]

Objective. To explore whether Stromal Interaction Molecule-1 (STIM1) participates in the phenotypic transformation of NRK-52E cells under high-calcium microenvironment. Materials and Methods. NRK-52E cells were treated with high concentration of calcium. The viability and apoptosis of cells were detected by CCK-8 (cell counting kit-8) and flow cytometry, respectively. The expression changes of phenotypic marker proteins (E-cadherin and OPN) and calcium channel proteins (STIMl and Orai1) in high-calcium environment were detected by western blotting and real-time quantitative polymerase chain reaction. The expression of STIMl protein in NRK-52E cells was upregulated and downregulated by plasmid-STIM1 and plasmid-shRNA-STIMl, respectively. The expressions of phenotypic marker proteins after upregulation or downregulation of STIMl were detected again. Besides, the intracellular calcium concentrations of NRK-52E cells in different treatments were detected by flow cytometry. Results. High-calcium microenvironment can promote the phenotypic transformation and the adhesion of calcium salts in NRK-52E cells and simultaneously suppress the expression of STIMl protein in NRK-52E cells. Downregulation of STIMl protein could also promote the phenotype transformation, while both the gene silence of matrix gla protein (MGP) and overexpression of STIMl showed reverse results. Conclusion. STIMl protein plays an important role in promoting phenotypic transformation of NRK-52E cells in high-calcium microenvironment. [ABSTRACT FROM AUTHOR]

In this paper, a low‐profile and wideband circularly polarized patch antenna using four resonance modes is presented. It is one kind of four‐port antenna implemented by loading five shorting pins on the circular patch. In order to achieve wideband properties, TM11 and TM22 modes are stimulated in circular patch, along with their polarization orthogonal modes (TM11+ and TM22+ modes). The TM11+ mode is excited by the Γ‐shaped feed, while the TM22 mode and TM22+ mode is stimulated by four shorting pins in close proximity to the Γ‐shaped feed. Due to the strong coupling between shorting pins and Γ‐shaped feed, the peak electric field generated on the two opposing shorting pins causes the magnetic current density on the circumference of the patch to be changed, which in turn leads to the realization of broadside radiation in the TM22 and TM22+ modes. In addition, the function of the shorting pin loaded in the center of the patch is to improve the impedance matching when TM22 and TM22+ modes are operated. Cooperated with the devised one‐to‐four feed network with equal amplitude and progressive phase difference of 90°, the wideband circularly polarized patch antenna is obtained. To verify this design concept, a prototype is fabricated and measured. The diameter of the patch is 0.68λ0 and the profile is 0.078λ0 (λ0 is the wavelength in the free space at the center frequency). The measured relative bandwidth of VSWR < 2 is 106%, involving 1.53–4.96 GHz, while that of AR < 3 dB is 98%, ranging from 1.54 to 4.48 GHz. Besides, the measured LHCP gain > 3 dBic in the frequency band of 1.48–4.42 GHz. [ABSTRACT FROM AUTHOR]

Electroacupuncture (EA) is a popular therapeutic therapy for premature ovarian insufficiency (POI). However, little has been known about the underlying processes of EA therapy. To investigate the benefit of EA and reveal the mechanism, thirty SD female rats were allocated into the control, model, sham, EA, and GnRHa groups at random. Vaginal smears were used to monitor the rats' estrous cycle. Serum liver and renal function (ALT, AST, BUN, and Cr), sex hormone (FSH, E2, and AMH), oxidative stress markers (SOD, GSH, and MDA), and inflammatory cytokine (IL6, IL1β, and TNFα) levels were measured by enzyme-linked immunosorbent assay (ELISA). Their ovary morphology was observed by hematoxylin-eosin staining. Transmission electron microscope was used to remark the ultrastructure of the granulocytes. Protein and gene expressions of Keap1/Nrf2/HO-1 pathway were detected by western blot and RT-PCR. Compared with the model group, in the EA group, the levels of serum sex hormones recovered to normal levels. Moreover, it reduced oxidative stress in rats, as demonstrated by increased SOD and GSH levels and decreased MDA levels. Meanwhile, Keap1 mRNA and protein expression dropped considerably in the EA group, while the mRNA and protein expressions of Nrf2 and HO-1 increased. We found that preventive EA might rescue rats with CTX-induced ovarian dysfunction. The anti-inflammatory and antioxidative stress properties of EA, which elevated the Keap1/Nrf2/HO-1 signaling pathway, might be the underlying mechanism. Furthermore, as compared to GnRHa, electroacupuncture did not raise the burden of the liver (ALT and AST) or the kidney (BUN and Cr). Electroacupuncture has a meaningful impact and a sufficient level of safety, making it useful for therapeutic setting in POI. [ABSTRACT FROM AUTHOR]