The THz-radiation power from bulk InAs irradiated with femtosecond optical pulses is significantly enhanced and reaches 650 μW in a 1.7-T magnetic field with 1.5-W excitation power. The THz-radiation power is related almost quadratically both to the magnetic field and excitation laser power. We have also found that the power of the THz-radiation from an InAs sample in a magnetic field is over one order of magnitude higher than that from GaAs. Additionally, a dramatic change of ellipticity is observed, and the spectra of the horizontal and vertical polarization components are found to differ.
Abstract. Epidermal growth factor receptor (EGFR) signaling regulates glioblastoma cell proliferation, survival, migration and invasion and plays a key role in tumor progression. We show that microRNA-7 (miR-7) is a common regulator of the phosphoinositide-3-kinase (PI3K)/ATK and Raf/ mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) pathways, both of which are launched by EGFR through its two direct targets, the transcription factors PI3K and Raf-1, respectively. Enforced expression of miR-7 markedly decreased expression of PI3K, phosphorylated Akt, Raf-1, phosphorylated MEK 1/2, and cyclin D1, as well as slightly reduced expression of EGFR. Forced expression of PI3K or Raf-1 transcripts lacking the 3'-untranslated region (3'-UTR) partially reversed the effects of miR-7 on cell growth inhibition and cell cycle arrest in glioma cells. Additionally, transient expression of miR-7 in glioblastoma cells strongly inhibited in vivo glioblastoma xenograft growth. We conclude that miR-7 is a potential tumor suppressor in glioblastoma that acts by targeting multiple oncogenes related to the downstream pathway of EGFR and may serve as a novel therapeutic target for malignant gliomas.
A capsule catalyst for isoparaffin synthesis based on Fischer-Tropsch reaction was designed by coating a H-ZSM-5 membrane onto the surface of the pre-shaped Co/SiO(2) pellet. Morphological and chemical analysis showed that the capsule catalyst had a core-shell structure. A compact, integral shell of H-ZSM-5 crystallized firmly on the Co/SiO(2) substrate without crack. Syngas passed through the zeolite membrane to reach the Co/SiO(2) catalyst to be converted, and all hydrocarbons formed with straight chain structure must enter the zeolite channels to undergo hydrocracking as well as isomerization in this tailor-made confined reaction environment. A narrow, anti-Anderson-Schultz-Flory law product distribution was observed on these capsule catalysts. Contrary to a mechanical mixture of H-ZSM-5 and Co/SiO(2), C(10+) hydrocarbons were suppressed completely on this novel capsule catalyst, and the selectivity of middle isoparaffins was considerably improved. The carbon number distribution of the products depended on the thickness of the zeolite membrane, and it was possible to selectively synthesize specified distillates, such as gasoline-range, or heavier hydrocarbons from syngas directly, by simply adjusting the thickness of the zeolite membrane of the capsule catalyst. This kind of capsule catalysts can be extended to various consecutive reaction systems as the shell and core components are independent catalysts for different reactions. At the same time, shape selectivity and space-confined effects can be expected for the reactant, intermediates and product of the sequential reactions.
The generation of cubicon pulses from an Yb fiber chirped pulse amplification system at pulse energies up to 200 microJ is demonstrated. After pulse compression 650 fs pulses with a pulse energy of 100 microJ are obtained, where pulse compression relies on the compensation of third-order dispersion mismatch between the stretcher and compressor via self-phase modulation of the cubicon pulses in the fiber amplifier. Values of self-phase modulation well in excess of pi can be tolerated for cubicon pulses, allowing for the nonlinear compensation of very large levels of dispersion mismatch between pulse stretcher and compressor.
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