Effects of ß-glucosidase and α-rhamnosidase on the Contents of Flavonoids, Ginkgolides, and Aroma Components in Ginkgo Tea Drink.

Ginkgo tea is a kind of health food produced from Ginkgo biloba leaves. The market of Ginkgo tea encountered many difficulties because of its bad palatability and vague function statement. In this study, two kinds of glycosidase were used to improve the flavor of Ginkgo tea, and three kinds of bioactivities were selected to investigate the health care function of the tea infusion. The aroma components extracted by headspace absorb (HSA) method during the making of Ginkgo tea were analyzed by GC-MS. The flavonoids and ginkgolides released into the tea infusion were studied by HPLC. A combination of ß-glucosidase (ß-G) and α-rhamnosidase (α-R) was applied during the making of the tea. The contents of characteristic aroma components and the release of total flavonoids and ginkgolides were increased significantly by adding ß-G and α-R. The composition of flavone glycosides was changed greatly. The free radical scavenging, inhibition of inflammatory cell activation, and tumor cytotoxicity activities of the tea were demonstrably improved. According to the release of active components, Ginkgo tea can be brewed repeatedly for at least three times. The enzymes used here show potential application prospects in the making of Ginkgo tea or tea drink to get higher contents of flavonoids, ginkgolides, and aroma components.

Nanopatterned luminescent concentrators for visible light communications.

Visible light communication (VLC) is a promising candidate for high-speed wireless communication with numerous unlicensed spectrum. To achieve high-speed data communication, it requires intense light signals concentrated on a tiny fast photodiode. The common way of using focusing optics reduces the field of view (FoV) of the photodiode due to the conservation of étendue. Luminescent solar concentrators (LSC) provide a solution to enhance the signals without affecting the FoV. In this paper we demonstrate nanopatterned LSCs fabricated on flexible plastics that achieve a doubling of optical gain compared to its traditional rectangular counterparts. These LSCs can free VLC detectors from complex active pointing and tracking systems, making them compatible with smart mobile terminals in a simple fashion.

Modification to increase the thermostability and catalytic efficiency of α-L-rhamnosidase from Bacteroides thetaiotaomicron and high-level expression.

The α-L-rhamnosidase BtRha from Bacteroides thetaiotao VPI-5482 is a specific enzyme that selectively hydrolyzes the α-1,2 glycosidic bond between rhamnose and rhamnose, allowing the bioconversion of epimedin C to icariin. In this study, BtRha was molecularly modified using B-factor-saturation mutagenesis strategy and the introduction of disulfide bonds, resulting in a mutant with significantly improved catalytic efficiency, S592C, and two thermally stable mutants, E39W and E39W-S592C. The results showed that the half-lives of E39W and E39W-S592C at 55 °C were 10.4 and 9.4-fold higher, respectively, than that of the original enzyme, The mutant S592C showed a 63.3% reduction in Km value and a 163.6% increase in catalytic efficiency (kcat/Km value), which improved the ability to hydrolyze epimedin C to icariin effectively. In addition, high-level expression of α-L-rhamnosidase mutant S592C was established. With 0.1 mM IPTG as an inducer, induction temperature of 32 °C, induction pH of 7.0 and induction OD600 of 50, the maximum activity of mutant S592C reached 182.0 U/mL in terrific broth medium after 22 h. This is the highest enzyme activity of α-L-rhamnosidase which can convert epimedin C to icariin to date. All the results provide a specific and cost-effective α-L-rhamnosidase mutant, which will raise its potential interest for the food and pharmaceutical applications.

Highly Efficient Blue-Emitting CsPbBr3 Perovskite Nanocrystals through Neodymium Doping.

Colloidal CsPbX3 (X = Br, Cl, and I) perovskite nanocrystals exhibit tunable bandgaps over the entire visible spectrum and high photoluminescence quantum yields in the green and red regions. However, the lack of highly efficient blue-emitting perovskite nanocrystals limits their development for optoelectronic applications. Herein, neodymium (III) (Nd3+) doped CsPbBr3 nanocrystals are prepared through the ligand-assisted reprecipitation method at room temperature with tunable photoemission from green to deep blue. A blue-emitting nanocrystal with a central wavelength at 459 nm, an exceptionally high photoluminescence quantum yield of 90%, and a spectral width of 19 nm is achieved. First principles calculations reveal that the increase in photoluminescence quantum yield upon doping is driven by an enhancement of the exciton binding energy due to increased electron and hole effective masses and an increase in oscillator strength due to shortening of the Pb-Br bond. Putting these results together, an all-perovskite white light-emitting diode is successfully fabricated, demonstrating that B-site composition engineering is a reliable strategy to further exploit the perovskite family for wider optoelectronic applications.