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A new strategy via coupling a polyol route with an oxidation process has been developed to successfully synthesize p-n junction CuO/BiVO4 heterogeneous nanostructures. The experimental results reveal that the as-prepared p-n junction CuO/BiVO4 heterogeneous nanostructures exhibit much higher visible-light-driven photocatalytic activity for the degradation of model dye rhodamine B (RhB) than the pure BiVO4 nanocrystals. The photocatalytic degradation rate (C/C0) of the RhB for p-n junction CuO/BiVO4 heterogeneous nanostructures is about two times higher than that of pure BiVO4 nanocrystals. The enhanced photocatalytic efficiency is attributed to a large number of p-n junctions in CuO/BiVO4 heterogeneous nanostructures, which effectively reduces the recombination of electrons and holes by charge transfer from n-type BiVO4 to the attached p-type CuO nanoparticles. This work not only provides an efficient route to enhance the visible-light-driven photocatalytic activity of BiVO4, but also offers a new strategy for fabricating p-n junction heterogeneous nanostructure photocatalysts, which are expected to show considerable potential application in solar-driven wastewater treatment and water splitting.

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Heterogeneous p-n junction CdS/CuO nanorod arrays have been fabricated by using a facile successive ionic-layer adsorption and reaction process to grow CuO nanoparticles on the surface of ordered CdS nanorod arrays. The heterogeneous p-n junction nanorod arrays exhibit superior photoelectrochemical performance for hydrogen (H) generation and high stability under visible-light irradiation. The highest photocurrent density achieved by heterogeneous nanorod array photoelectrode is 4.2 mA cm in a sacrificial NaS and NaSO mixture electrolyte solution at 0 V versus Ag/AgCl, which is 4 times higher than that of a pure CdS nanorod array photoelectrode. In addition, the heterogeneous nanorod array photoelectrode achieves an incident photon conversion efficiency value of 40.5% at 470 nm. The photocatalytic hydrogen generation rate of the heterogeneous nanorod array photoelectrode reaches up to 161.2 μmol h, around 3-fold increase compared to that of a bare CdS photoelectrode. Furthermore, the heterogeneous p-n junction CdS/CuO nanorod arrays show an excellent stability under long light illumination of 7200 s. The improved photoelectrochemical performance, photocatalytic activity, and excellent stability of the heterogeneous nanorod array photoelectrode resulted from the efficient separation of photoinduced electron-hole pairs, which is achieved by the synergistic effects of CdS, CuO, p-n junction, and an inner electric field in the photoelectrode. The present work provides a new strategy to fabricate a heterogeneous photoelectrode. This facile strategy is expected to be utilized to fabricate electrodes of other materials for highly efficient solar-driven water splitting application.

Ginseng is an economically important medicinal plant. The major bioactive ingredients of ginseng are ginsenosides, which are triterpene saponins. Because of difficulties in ginseng cultivation and the low productivity of ginseng cell and tissue culture, it has become important to improve ginsenoside levels by using metabolic engineering based on the biosynthetic pathway of ginsenosides. During the last decade, substantial advances have been made in biosynthesis of ginsenosides. This review is concerned with recent developments in our understanding of the biosynthesis of ginsenosides.

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Ginsenosides, a kind of triterpenoid saponins derived from isopentenyl pyrophosphate (IPP), represent the main pharmacologically active constituents of ginseng. In plants, two pathways contribute to IPP biosynthesis, namely, the mevalonate pathway in cytosol and the non-mevalonate pathway in plastids. This motivates biologists to clarify the roles of the two pathways in biosynthesis of IPP-derived compounds. Here, we demonstrated that both pathways are involved in ginsenoside biosynthesis, based on the analysis of the effects from suppressing either or both of the pathways on ginsenoside accumulation in Panax ginseng hairy roots with mevinolin and fosmidomycin as specific inhibitors for the mevalonate and the non-mevalonate pathways, respectively. Furthermore, the sterol biosynthesis inhibitor miconazole could enhance ginsenoside levels in the hairy roots. These results shed some light on the way toward better understanding of ginsenoside biosynthesis.

The Bayesian network meta-analysis suggests that GLP-1 RAs were associated with a decreased bone fracture risk compared to users of placebo or other anti-hyperglycemic drugs in type 2 diabetes mellitus patients, and exenatide is the best option agent with regard to the risk of fracture.