Observation of photonic Peierls transition for manipulating microwave in metallic diaphragm-array periodic structures.

Peierls transition that modifies electronic band structure has attracted intensive attention in solid state physics. In the present work, we report that a photonic analog of Peierls transition has been observed in a 1-D triangular metal diaphragm array, where the photonic bandgap structures have been designed at will by adjusting periodically metal diaphragm positions. It is shown by the numerical analysis that the transmission and radiation effect of the present periodic metal structure designed through the Peierls transition rule exhibits the behavior significantly different from an original periodic structure with each unit cell containing a metal diaphragm. The near- and far-field measurement results are in good agreement with our theoretical simulation. The present effect of photonic Peierls transition can serve as a working mechanism for designing new types of guided wave devices. It can be seen that the photonic Peierls transition would be one of the simplest ways for modifying the transport characteristics of electromagnetic waves in periodic structures.

A kind of planar waveguides for cheating the high-speed digital signals into misidentifying the characteristic impedance.

Since a planar periodic transmission line can suppress drastically the electromagnetic coupling, it would be advantageous to use such a kind of transmission lines in solving the problem of miniaturization of circuit area. By adjusting the lattice constants and geometric parameters of periodic microstrip lines, a time domain characteristic impedance that is the same as that of conventional microstrip lines (CMLs) can be achieved. Such periodic microstrip lines can therefore be used to trick high-speed digital signals, causing a digital signal to misjudge the time domain characteristic impedance of the transmission lines. The theoretical analysis has been verified by our experimental measurement results. Besides, a specific expression for the characteristic impedance of lossless periodic artificial materials is deduced by a circuit model and a standard of misidentification for the characteristic impedance of periodic microstrip lines is given for the digital signals.

MicroRNA-217 functions as a tumor suppressor in cervical cancer cells through targeting Rho-associated protein kinase 1.

The abnormal expression of microRNAs (miRNAs/miRs) has been widely reported in various tumor types. miR-217 was demonstrated to be aberrantly expressed in a number of tumors, including pancreatic adenocarcinoma and osteosarcoma; however, its specific expression pattern has never been investigated in cervical cancer cells. Compared with normal control, the level of Rho-associated protein kinase 1 (ROCK1) expression was markedly increased in cervical cancer tissues and cells compared with that in non-cancerous tissues and cells. The expression of miR-217 was significantly reduced in cervical cancer tissues and cell lines. Overexpression of miR-217 could suppress colony formation and the cell invasion capacity of SiHa and HeLa cells. Flow cytometry indicated that miR-217 significantly increased cell apoptosis in SiHa and HeLa cells. Dual-luciferase reporter assays demonstrated that ROCK1 was a target gene of miR-217. In addition, overexpression of ROCK1 also led to an increased invasion capacity in SiHa cells, even when miR-217 was inhibited, indicating that the anti-invasive effects of miR-217 were mediated through ROCK1. In summary, the results of the present study indicated that miR-217 functions as a tumor suppressor in cervical cancer cells, primarily by targeting ROCK1.