Displacement Reaction-Assisted Synthesis of Sub-Nanometer Pt/Bi Boost Methanol-Tolerant Fuel Cells.

The development of new synthetic methods for methanol-tolerant catalysts with improved performance is of fundamental importance for the commercialization of fuel cells. Herein, we reported a facile displacement reaction-assisted synthesis of graphene-supported sub-nanometer Pt/Bi catalysts (Pt/Bi/rGO). Bismuth (0) nanoparticles produced by NH3BH3 reduction can be further dissolved into the ethylene glycol, implying Bi(0) has a strong interaction with the hydroxyl group. That is the key interaction between Bi(0) and the functional group on the rGO to form the ultra-small Bi/rGO catalyst. Furthermore, Pt clusters are obtained by the displacement between Bi(0) and HPtCl4 and are directly anchored to the rGO surface. The as-synthesized Pt/Bi/rGO catalyst exhibits high oxygen reduction mass activity and high tolerance to methanol poisoning. In the presence of 0.5 mol/L CH3OH, the initial potential and activity of ORR were almost unchanged, which demonstrated great potential in the application of direct methanol fuel cells.

Abnormality of Klotho Signaling Is Involved in Polycystic Ovary Syndrome.

This study investigated the involvement of the klotho-associated signaling in the apoptosis of granulosa cells (GCs) from the ovaries of patients with polycystic ovary syndrome (PCOS) and PCOS animals. Primary GCs were obtained from 26 healthy women and 43 women with PCOS. The PCOS animal model was established by the injection of dehydroepiandrosterone (DHEA). Klotho protein and associated microRNA expression in human primary GCs and rats' ovarian tissues were measured by Western blot and real-time polymerase chain reaction, respectively. Results showed that significantly lower miR-126-5p and miR-29a-5p microRNA expressions, higher klotho protein expression, lower insulin growth factor 1 (IGF-1R) and Wnt family member 1 (Wnt1) protein expressions, and lower Akt phosphorylation at Ser473 and Thr308 residues were observed in the GCs from patients with PCOS and the ovarian tissues of PCOS rats compared to that in GCs from healthy women and ovarian tissues of normal control rats, respectively. Knockdown of klotho gene expression normalized IGF-1R and Wnt1 protein expressions and Akt phosphorylation in GCs from patients with PCOS and the ovarian tissues from PCOS rats; it also blocked the effects of insulin on apoptosis and proliferation in GCs from patients with PCOS and inhibited caspase-3 activity in ovarian tissues of PCOS rats. Knockdown of klotho gene expression increased the pregnancy rate in DHEA-treated female rats and increased the body weight of their newborns through normalizing the ovarian function and decreasing the formation of cystic follicles. In conclusion, the miR-126-5p, miR-29a-5p/klotho/insulin-IGF-1, Wnt, and Akt signal pathway may be involved in the apoptosis of GCs and subsequent development of PCOS.

Isolation, purification, characterization and immunostimulatory activity of polysaccharides derived from American ginseng.

In this study, crude American ginseng polysaccharide (AGPS) was extracted with hot water and preliminarily purified by using resin S-8 and Polyamide columns. Then, it was further purified and separated by DEAE-Sepharose CL-6B and Sepharose CL-6B chromatography, respectively. Five main fractions were obtained, named WPS-1, WPS-2, SPS-1, SPS-2 and SPS-3. Their homogeneities and structural characteristics were elucidated based on UV-vis spectroscopy, High Performance Gel Filtration Chromatography (HPGFC), Gas Chromatography (GC), Scanning Electron Microscopy (SEM), Infrared Spectrum (IR), and NMR Spectroscopy methods. Furthermore, the immunostimulatory effects of these fractions upon splenic lymphocyte proliferation, macrophage phagocytosis and nitric oxide (NO) production, were investigated in vitro. The results indicated that their stimulations could be ordered as SPS-3>SPS-1>CPS (crude polysaccharides)>WPS-1>WPS-2>SPS-2. Among them, SPS-3 showed more potent immunomodulatory activity and could be explored as a potential immunopotentiating agent for use in functional food or medicine.