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The four-port cavity model is presented to study a differential dual-polarised annular-ring patch antenna operating at higher order mode TM12. Acceptable agreements among calculated, simulated, and measured impedances and radiation patterns are obtained. Theoretical analysis shows that the differential port-to-port coupling impedance is zero, and its isolation is theoretically infinite. The differential input impedance is about four times of the single-ended input impedance at the resonant frequency of higher order mode TM12. The differential operation can suppress the adjacent modes TM02 and TM22 near the operating mode TM12 and lead to a more symmetrical E-plane radiation pattern and lower cross polarisation level. [ABSTRACT FROM AUTHOR]

This paper presents a novel tunable microstrip patch antenna using liquid crystal. It adopts a differentially-driven, aperture-coupled, and stacked-patch structure. Compared with the conventional design, this novel antenna achieves a larger frequency tuning range, much wider impedance bandwidth, higher radiation efficiency and gain. Besides, the novel antenna facilitates the bias design as the bias signal is naturally isolated from the RF signal. Both the conventional and novel antennas are designed to operate at 28GHz using an RT/Duroid 5880 substrate and K15 liquid crystal. Results show that the novel antenna has a tuning range of 3.1%, an impedance bandwidth of 6.43%, a peak radiation efficiency of 70%, and a peak realized gain of 6.5 dBi, while the conventional antenna has the tuning range of 2.7%, impedance bandwidth of 3.57%, peak radiation efficiency of 45%, and peak realized peak gain of 4.5 dBi. [ABSTRACT FROM AUTHOR]

The cavity model is extended to analyze a dual-probe-feed circular microstrip patch antenna for both differential and single-ended operations. Particular emphasis is given to the impedance characteristics in order to understand the relationship between the differential and single-ended input impedances. It is shown that the differential input resistance is four times of the single-ended input resistance at the resonant frequency of the fundamental mode. [ABSTRACT FROM PUBLISHER]

A new type of half-mode substrate integrated waveguide (SIW) periodically loaded with different lumped elements and structures is proposed in this paper. The propagation constants, Bloch impedances, and voltage distributions of the Floquet TE-modes are all characterized by solving the eigenvalues of the generalized transmission matrix of a single period. Several typical capacitor-loaded, inductor-loaded, corrugated, and electromagnetic- bandgap (EBG)-loaded half-mode SIWs were fabricated to demonstrate their modal dispersion behavior. The measured and simulated S-parameters, group delays, and simulated electric field distributions in these novel structures are presented, with good agreements obtained for all samples. In particular, their unique controllable cutoff frequencies, multiple bandgaps, and separated monomode regions are also illuminated numerically and experimentally. To further show their applications, a tunable phase shifter is developed using a varactor-loaded structure, with its 3-dB bandwidth of 50% and a maximal tunable range of 88° . In addition, a bandpass filter based on EBG-loaded half-mode SIW is also realized and presented with its special characteristics. It demonstrates that the filter has a sharp upper slope side and a good performance of spurious suppression. [ABSTRACT FROM AUTHOR]

AbstractAim:Baicalin, one of the major flavonoids in Scutellaria baicalensis, possesses antioxidant and anti-inflammatory properties. However, the effects of baicalin on metabolic disorders and hepatic steatosis have not been investigated.Methods:Body weight was examined in high-fat diet (HFD)-fed rats with or without baicalin treatment. At the end of the experiment, serum biochemical parameters, liver histology and lipid profile were analyzed to assess whether the animals were suffering from metabolic disorders or hepatic steatosis. In the liver, the phosphorylation of AMP activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) and the gene expression of some enzymes involved in lipogenesis were examined. The effects of baicalin on the phosphorylation of AMPK and lipid accumulation induced by high glucose in human hepatoma HepG2 cells were also examined.Results:Baicalin (80 mg/kg) administered ip for 16 weeks suppressed body weight gain in HFD-fed rats. Weight reduction was accompanied by the reduction of visceral fat mass. Baicalin significantly decreased the elevated serum cholesterol, free fatty acid and insulin concentrations caused by the HFD. Baicalin also suppressed systemic inflammation by reducing the serum level of tumor necrosis factor α. Baicalin reduced hepatic lipid accumulation, enhanced the phosphorylation of AMPK and ACC and down-regulated genes involved in lipogenesis, including fatty acid synthase and its upstream regulator SREBP-1c. In HepG2 cells, baicalin (5 and 10 μmol/L) increased the phosphorylation of AMPK and decreased lipid accumulation following the addition of high glucose.Conclusion:Our study suggests that baicalin might have beneficial effects on the development of hepatic steatosis and obesity-related disorders by targeting the hepatic AMPK. [ABSTRACT FROM AUTHOR]

Determines the effect of acidosis on tension and [Ca2+]i in rat cerebral arteries. Measurement of force and membrane potential; Determination of pH dependence of dissociation constant of fura 2; Effect of hypercapnic and normocapnic acidosis on membrane potential and force.