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Major depressive disorder has become one of the most serious neuropsychiatric disorders worldwide. However, currently available antidepressants used in clinical practice are ineffective for a substantial proportion of patients and always have side effects. Besides being a lipid-regulating agent, gemfibrozil is an agonist of peroxisome proliferator-activated receptor-α (PPAR-α). We investigated the antidepressant effects of gemfibrozil on C57BL/6J mice using the forced swim test (FST) and tail suspension test (TST), as well as the chronic unpredictable mild stress (CUMS) model of depression. The changes in brain-derived neurotrophic factor (BDNF) signaling cascade in the brain after CUMS and gemfibrozil treatment were further assessed. Pharmacological inhibitors and lentivirus-expressed short hairpin RNA (shRNA) were also used to clarify the antidepressant mechanisms of gemfibrozil. Gemfibrozil exhibited significant antidepressant actions in the FST and TST without affecting the locomotor activity of mice. Chronic gemfibrozil administration fully reversed CUMS-induced depressive-like behaviors in the FST, TST and sucrose preference test. Gemfibrozil treatment also restored CUMS-induced inhibition of the hippocampal BDNF signaling pathway. Blocking PPAR-α and BDNF but not the serotonergic system abolished the antidepressant effects of gemfibrozil on mice. Gemfibrozil produced antidepressant effects in mice by promoting the hippocampal BDNF system.

Symmetric structures of single and dual-band metamaterial in the terahertz region are proposed, which composed of the electrical inductance-capacitance (ELC) resonate and electric field coupling resonate. Simulation results show that it can perform absorption peaks at one resonant frequency 0.716 THz with the absorption more than 95%, and at two distinct resonant frequencies 0.612 THz and 1.086 THz with the absorption above 90%. These models have the advantages of simple structure and strong absorption, due to the well-separating of different resonances in the particle, this metamaterial shows potentially application promises in the design of multiband terahertz devices.

Terahertz filter based on a composite metal-dielectric-metal structure is proposed. Different transmission characteristics of stop-band are shown for different polarizations of the THz radiation. The causes of dual-layer structure with characteristics of filter have been analyzed qualitatively using simple cascading multiplication. The near-field distributions of the planar microstructures are given to further elaborate the mechanisms of filter. Besides, tuning bandwidths and center frequencies can be realized by modulating the main parameters of the structure.

A small-sized compact CPW feed ultra-wideband (UWB) antenna with dual-band notched characteristic is proposed. The antenna consists of the radiation pattern, ground plane and the CPW feed on one side of the substrate, which is used to support the antenna and on the other side are two resonators with filter characteristic. By integrating the filters with the antenna, the antenna can suppress the WLAN band (5.15 ~ 5.35 GHz and 5.725 ~ 5.825 GHz) successfully which makes the use of the frequency resource and decreases the electromagnetic interference (EMI). The size of the band-rejected antenna is small, just 24 mm × 30 mm × 0.5 mm.