802.16/WiMAX is going to be the most popular technology in wireless communications. In 2006, IEEE 802.16e has been proposed for mobility issue. In order to maintain security, re-authentication should be considered when the mobile station handovers. However, re-authentication often takes latency and consumes power. On the other hand, several fast authentication schemes have been proposed based on preauthentication concept in 802.11/WLAN networks. These schemes provide different methods to enhance the efficiency and security of re-authentication procedure. By using the preauthentication concept, we propose a pre-authentication scheme for WiMAX infrastructures in this paper. Due to flexibility and security, the proposed scheme is combined with the PKI architecture. It provides a secure and fast re-authentication procedure during macro-handover in 802.16/WiMAX networks.

In optogenetics, red-shifted channelrhodopsins (ChRs) are eagerly sought. We prepared six kinds of new chromophores with one double bond inserted into the polyene side chain of retinal (A1) or 3,4-didehydroretinal (A2), and examined their binding efficiency with opsins (ReaChR and ChrimsonR). All analogs bound with opsins to afford new ChRs. Among them, A2-10ex (an extra double bond is inserted at the C10-C11 position of A2) showed the greatest red-shift in the absorption spectrum of ChrimsonR, with a maximum absorbance at 654 nm (67 nm red-shifted from that of A1-ChrimsonR). Moreover, a long-wavelength spectral boundary of A2-10ex-ChrimsonR was extended to 756 nm, which reached into the far-red region (710-850 nm).