Novel 2-Benzo[d]thiazolyl-4-quinolinylphenol Skeleton-Based Turn-on Fluorescent Probe for H2S Detection and its Multiple Applications in Water Environment, Foodstuffs, and Living Organisms.

Hydrogen sulfide (H2S) has comprehensive contributions to maintaining the normal operation and stability of organisms, and it also occurs in the wastewater environment and is related to the deterioration of foodstuffs. Therefore, developing high-sensitive detection techniques for tracing H2S is promising and meaningful. Inspired by this, a novel nopinone-based fluorescent probe NPS for the recognition of H2S was designed and synthesized with excellent sensitivity, low limit of detection (79 nM), good selectivity, and wide pH range (5-9). NPS could emit strong yellow fluorescence and its emission intensity showed a remarkable augmentation at 520 nm upon the supplement of H2S. Furthermore, the recognition mechanism of NPS for H2S was verified by the HRMS analysis, 1H NMR spectra titration, and DFT computation. What is more, NPS also had broad applications in the monitoring of real water samples, red wine, beer, and eggs samples, which showed its development prospect and value in environmental pollution, foodstuffs quality analysis fields. NPS also was applied to monitor trace exogenous H2S and bioimaging in living cells and zebrafish.

Flexoelectric and dielectric effects in uniform lying helix cholesteric liquid crystals under cell boundary conditions.

 Flexoelectric effect and dielectric effect in uniform lying helix (ULH) cholesteric liquid crystals under cell boundary conditions of periodic anchoring at the bottom and vertical anchoring at the top are studied. They can be quantitatively analyzed by theoretically simulation of the polar angle and the tilt angle. It is found that a good ULH texture can be formed inside under periodic boundary conditions and the bulk director is not affected by the surface anchoring strength. The induced rotation angle of the helical axis by the flexoelectric effect is slightly non-uniform with the position, and the coupling of the flexoelectric effect and dielectric effect increases the inhomogeneous change. Our results will provide an accurate theory basis for the formation of a good ULH texture and the influence of dielectric effect on the optical axis.