Polarization-independent and high-efficiency dielectric metasurfaces for visible light.

Dielectric metasurfaces are capable of completely manipulating the phase, amplitude, and polarization of light with high spatial resolutions. The emerging design based on high-index and low-loss dielectrics has led to the realization of novel metasurfaces with high transmissions, but these devices usually operate at the limited bandwidth, and are sensitive to the incident polarization. Here, we report the realization of the polarization-independent and high-efficiency silicon metasurfaces spanning the visible wavelengths about 200 nm.

Visible-Frequency Dielectric Metasurfaces for Multiwavelength Achromatic and Highly Dispersive Holograms.

Dielectric metasurfaces built up with nanostructures of high refractive index represent a powerful platform for highly efficient flat optical devices due to their easy-tuning electromagnetic scattering properties and relatively high transmission efficiencies. Here we show visible-frequency silicon metasurfaces formed by three kinds of nanoblocks multiplexed in a subwavelength unit to constitute a metamolecule, which are capable of wavefront manipulation for red, green, and blue light simultaneously. Full phase control is achieved for each wavelength by independently changing the in-plane orientations of the corresponding nanoblocks to induce the required geometric phases.

[Determination and fingerprint analysis of tetramethylpyrazine and ferulic acid in Ligusticum chuanxiong].

Objective: To determine the contents of tetramethylpyrazine (TMP) and ferulic acid in Ligusticum chuanxiong from different producing areas and seasons.

Methods: The contents of TMP and ferulic acid were determined by HPLC, and then analyzed by Chromatographic Fingerprints.

Results: The contents of TMP and ferulic acid from different seasons were obviously different from each other.

Hyperoxia increases AP-1 DNA binding in rat brain.

Oxidative stress appears to contribute to neurodegenerative outcomes after ischemia, hypoxia, and hyperoxia. The AP-1 transcription factor is made up of a family of regulatory proteins that can be activated by oxidative stress. In the present study, we examined AP-1 DNA binding activity in terms of specific participating AP-1 proteins in rat brain after hyperoxia.

Attenuated transcriptional responses to oxidative stress in the aged rat brain.

The aged nervous system displays impaired cognitive functions, and these impairments are exacerbated in several neurodegenerative diseases. A role for oxidative stress has been suggested for several of these age-associated dysfunctions. In addition, recovery from more acute traumatic insults that also generate oxidative stress is impaired in the aged.