Electromagnetically induced transparency metamaterial with polarization independence and multi-transmission windows.

In this paper, an electromagnetically induced transparency (EIT) metamaterial with the performances of polarization independence and multi-transmission windows is proposed. First, we design an EIT with a single transmission window, which is composed of an H-shaped structure and two split-ring resonators (SRRs). Then, by sequentially rotating the unit by 90°, a new EIT structure with rotational symmetry is obtained. The results show that the new EIT structure has the characteristics of polarization independence and multiple transmission windows, and each transmission window has a high maximum transmittance and group index. The first transmission window has a maximum group index of 88.9 and 98.9% maximum transmission. The maximum group indices of the second and third transmission windows are 117.9 and 215.3, and the peak transmissions are 89.9% and 97.4%, respectively. The multiple transmission windows with polarization independence widen the application scope of the proposed EIT metamaterial and are suitable for high-performance slow-wave devices with the above two requirements.

Synthesis of a novel series of diphenolic chromone derivatives as inhibitors of NO production in LPS-activated RAW264.7 macrophages.

A novel series of diphenolic chromone derivatives were synthesized and their inhibitory activity on nitric oxide (NO) production and cytotoxicity were evaluated using LPS-activated murine macrophages RAW264.7 assay and MTT method, respectively. Among these compounds, (5,7-dihydroxy-4-oxo-4H-chromen-3-yl) methyl esters (6b, 6c, 6f, 6g, and 6h) showed quite potent inhibitory activities with IC(50) values of 2.20, 3.48, 0.35, 0.80, and 0.61microM, respectively. The MTT results showed that all of the active compounds exhibited no cytotoxicity at the effective concentrations. The preliminary mechanism of the most potent compounds (6b, 6c, 6f, 6g, and 6h) was further examined based on the RT-PCR results and the compounds 6f, 6g, and 6h inhibited NO production by suppressing the expression of iNOS mRNA in a dose dependent manner. Furthermore, a computational analysis of physicochemical parameters revealed that the most of the compounds possessed drug-like properties.

Synthesis and evaluation of a novel series of quinoline derivatives with immunosuppressive activity.

A series of quinoline derivatives were synthesized and their immunosuppressive activity and cytotoxicity were evaluated with a T-cell functional assay and MTT method, respectively. Most of 5,7-dimethoxyquinolin-4-yl ortho-substituted benzoate derivatives (18, 22, 24, 28, 31 and 37) showed a quite stronger inhibitory activity compared to other analogs. Among the synthesized compounds, 5,7-dimethoxyquinolin-4-yl 2,6-dichlorobenzoate (22) and 5,7-dimethoxyquinolin-4-yl 4-methylbenzenesulfonate (40) exhibited a potent inhibitory activity without significant cytotoxicity at 10 microM concentration. The preliminary mechanism of the active compounds 22 and 40 was further clarified based on the fluorescence activated cell sorter (FACS) assay, and the compounds exerted immunosuppressive activity via inhibiting the T cell activation in a dose dependent manner.