Arbitrary and reconfigurable optical vortex generation:a high-efficiency technique using director-varying liquid crystal fork gratings

A high-efficiency technique for optical vortex(OV) generation is proposed and demonstrated. The technique is based on liquid crystal fork gratings with space-variant azimuthal orientations, which are locally controlled via polarization-sensitive alignment layers. Thanks to the optical rewritability of the alignment agent and the dynamic image generation of the digital micro-mirror device, fork gratings can be instantly and arbitrarily reconfigured.Corresponding optical vortices carrying arbitrary azimuthal and radial indices are demonstrated with a conversion efficiency of 98.5%, exhibiting features of polarization control and electrical switching. The technique may pave a bright road toward OV generation, manipulation, and detection.

Liquid crystal depolarizer based on photoalignment technology

We propose a depolarizer based on the principle of a collection of half-wave plates with randomly distributed optic axes. The design is demonstrated by means of dynamically photopatterning liquid crystal into randomly aligned homogeneous domains. We characterize the liquid crystal depolarizer for 1550 nm and C-band(1520–1610 nm). A degree of polarization of less than 5% is obtained for any linearly polarized light. This study provides a practical candidate for high-performance depolarizers.

Synthesis and Structure-Activity Relationships of Ring-Opened Bengamide Analogues against Methicillin-Resistant Staphylococcus aureus

Main observation and conclusion Methicillin-resistant Staphylococcus aureus(MRSA)has become a major threat on public health because of the increase of clinically isolated strains that exhibit resistance to many antibiotics.Therefore,development of new antibiotics for the treatment of MRSA in-fection is a sustained challenge.We have previously identified a ring-opened bengamide analogue L472-2 that displays moderate ac-tivity against the growth of S.aureus.In our previous work,we started from L472-2 and identified a class of analogues containing al-kynyl groups which have the potential to activate SaCIpP activity but moderate antibacterial activity.Herein,we focused on the anti-bacterial activity of L472-2,and a novel series of ring-opened bengamide analogues were synthesized and their activities were evalu-ated against MRSA.By conducting a compact analysis of the structure-activity relationships(SAR)of these analogues,we found that an adamantane ethanol ester bengamide 2j showed excellent antibacterial activity towards six S.aureus strains,including MRSA,while it does not activate CIpP.Therefore,these bengamide analogues represent a new class of candidates that suppress MRSA via-bility..

Design,Synthesis and Biological Evaluation of Bengamide Analogues as ClpP Activators

Summary of main observation and conclusion To combat multidrug-resistant Gram-positive bacteria,new antimicrobials particularly those with novel mechanism of action are badly needed.Different with conventional antibiotics which are typical inhibitors,small-molecule activators of bacterial CIpP represent a new class of antibiotics.No ClpP activator has been developed for clinical trial.Herein,we conducted a screening on our library of benga-mide-like ring opened analogues and found that L472-2 possesses a low minimum inhibitory concentration(MIC)against S.aureus and shows no activity for ClpP activation in vitro,but it displayed reduced antibacterial activity against S.aureus with clpP deletion.In order to obtain bengamide analogues that activate ClpP in vitro as well as possess antibacterial activity,we perform further structural modifications starting from L472-2.Compound 37 re-mains the antimicrobial activity and activation of ClpP protein in vitro,which could be viewed as a new chemical scaffold for ClpP activators and worthy of further investigation.