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Understanding the physics of low-dimensional systems and the operation of next-generation electronics will depend on our ability to measure the electrical properties of nanomaterials at terahertz frequencies (∼100 GHz to 10 THz). Single-walled carbon nanotubes are prototypical one-dimensional nanomaterials because of their unique band structure and long carrier mean free path. Although nanotube transistors have been studied at microwave frequencies (100 MHz to 50 GHz), no techniques currently exist to probe their terahertz response. Here, we describe the first terahertz electrical measurements of single-walled carbon nanotube transistors performed in the time domain. We observe a ballistic electron resonance that corresponds to the round-trip transit of an electron along the nanotube with a picosecond-scale period. The electron velocity is found to be constant and equal to the Fermi velocity, showing that the high-frequency electron response is dominated by single-particle excitations rather than collective plasmon modes. These results demonstrate a powerful new tool for directly probing picosecond electron motion in nanostructures. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs) present frequently altered expression in urologic cancers including prostate, bladder, and kidney cancer. The altered expression of miR-223 has been reported in cancers and other diseases in recent researches. MiR-223 is up-regulated in systemic lupus erythematosus and rheumatoid arthritis. In neoplastic diseases, miR-223 is proved to be up-expressed in plasma or serum and cancer tissues compared with normal tissues in pancreatic cancer, gastric cancer, et al. However, whether altered expression of miR-223 is associated with prostate cancer (PCa) and what it is potential functions in PCa remained unveiled. In this study, we firstly found miR-223-3p were up-regulated in prostate cancer tissues and then we study functional role of miR-223-3p in PCa using DU145, PC3 and LNCaP cell lines. Our data suggested that miR-223-3p might target gene SEPT6 and promoted the biological behavior of prostate cancer. Notably, we found increasing SEPT6 expression might reverse the biological activity induced by miR-223-3p, which might be a potential therapeutic target for PCa. [ABSTRACT FROM AUTHOR]