Improving near-infrared luminescence in Er doped CsPbBr quantum dots glasses through a certain energy transfer process.

Er has received extensive attention due to its excellent optical properties, especially its emission at 1535 nm in atmospheric propagation window. Enhancement and regulation of 1535 nm emission of Er is of great significance to optical communication. In this work, growing of CsPbBr QDs has been controlled through adjusting annealing time which would precisely regulate conduction band of CsPbBr QDs to match energy levels of Er enabling energy transfer between Er and CsPbBr QDs.

High-resolution laser induced excitation spectroscopy and decay dynamics of YNbO:Er.

The rare earth materials have attracted intensive attention due to their strong luminescent characteristic. However, the split fine Stark levels are difficult to be determined. Here we report a room-temperature detection for Stark levels of YNbO: Er using established laser-induced spectroscopy system with dye laser of superhigh resolution of wavelength at 0.

Structure-guided engineering of ChKRED20 from Chryseobacterium sp. CA49 for asymmetric reduction of aryl ketoesters.

ChKRED20 is a robust NADH-dependent ketoreductase identified from the genome of Chryseobacterium sp. CA49 that can use 2-propanol as the ultimate reducing agent. The wild-type can reduce over 100 g/l ketones for some pharmaceutical relevant substrates, exhibiting a remarkable potential for industrial application.

Crystal structure and iterative saturation mutagenesis of ChKRED20 for expanded catalytic scope.

ChKRED20 is an efficient and robust anti-Prelog ketoreductase that can catalyze the reduction of ketones to chiral alcohols as pharmaceutical intermediates with great industrial potential. To overcome its limitation on the bioreduction of ortho-substituted acetophenone derivatives, the X-ray crystal structure of the apo-enzyme of ChKRED20 was determined at a resolution of 1.85 Å and applied to the molecular modeling and reshaping of the catalytic cavity via three rounds of iterative saturation mutagenesis together with alanine scanning and recombination.

Single mutations of ketoreductase ChKRED20 enhance the bioreductive production of (1S)-2-chloro-1-(3, 4-difluorophenyl) ethanol.

(1S)-2-chloro-1-(3, 4-difluorophenyl) ethanol ((S)-CFPL) is an intermediate for the drug ticagrelor, and is manufactured via chemical approaches. To develop a biocatalytic solution to (S)-CFPL, an inventory of ketoreductases from Chryseobacterium sp. CA49 were rescreened, and ChKRED20 was found to catalyze the reduction of the ketone precursor with excellent stereoselectivity (>99 % ee).

Rapid asymmetric reduction of ethyl 4-chloro-3-oxobutanoate using a thermostabilized mutant of ketoreductase ChKRED20.

Ethyl (S)-4-chloro-3-hydroxybutanoate ((S)-CHBE) is an important chiral intermediate for the synthesis of "blockbuster" drug statins. The carbonyl reductase ChKRED20 from Chryseobacterium sp. CA49 was found to catalyze the bio-reductive production of (S)-CHBE with excellent stereoselectivity (>99.

Effect of the Hydrogen Bond on Photochemical Synthesis of Silver Nanoparticles.

The effect of a hydrogen bond on the photochemical synthesis of silver nanoparticles has been investigated via experimental and theoretical methods. In a benzophenone system, the photochemical synthesis process includes two steps, which are that hydrogen abstraction reaction and the following reduction reaction. We found that for the first step, an intermolecular hydrogen bond enhances the proton transfer.