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Oxygen reduction reaction (ORR) is a crucial cathodic reaction for fuel cells. Due to its sluggish kinetics, various ORR electrocatalysts have been designed and extensively investigated. Traditionally, Pt-based materials serve as efficient ORR catalysts. However, Pt’s low abundance, high cost and poor durability have compelled people to explore other materials. For example, silver (Ag) is comparatively well-stocked and low-cost, which has drawn great attention. Although Ag shows exceptional anti-poisoning property, it is not good as Pt. Recently, enhanced electrochemical behavior of plasmonic nanostructures under illumination has been examined through both theoretical modeling and experimental investigations. As a green and sustainable energy source, solar energy can be efficiently introduced into fuel cells and metal-air batteries. Plasmonic Ag nanoparticles have strong spectral absorption in the ultraviolet and visible light bands due to unique localized surface plasmon resonance effects. Meanwhile, nitrogen-doped graphene (NG) incorporates nitrogen (N) atoms into graphene skeleton through a hydrothermal process, thereby providing active ORR sites. Also, the vacancies and defects generated by the N-doping allow silver nanoparticles to be better dispersed on the graphene as well as maintain silver nanoparticles during the reaction. Herein, plasmonic Ag nanoparticles decorated N-doped graphene (Ag/NG) were synthesized and utilized as ORR catalysts. The ORR performance of Ag/NG greatly exceeded that of pure Ag nanoparticles and NG. For instance, the half-wave potential was 0.86 V, exceeding that of commercial Pt/C (20 wt. %). Under the AM1.5G simulated sunlight, Ag/NG demonstrated photo-enhanced electrocatalytic performance with right shifting of onset potential and enhanced current density. Therefore, the Ag/NG composite provides a potential strategy for the development of solar-enhanced electrocatalysts for fuel cells and metal-air batteries.

A simple template method is proposed for the synthesis of Ag nanoparticles embedded in Fe-N-C (Ag@FeNC) as excellent oxygen reduction reaction (ORR) catalyst. Firstly, Ag@Fe3O4 nanoparticles are synthesized and loaded onto graphene oxide to form the Ag@Fe3O4-GO template. The surface of the template is then enveloped by polypyrrole. After pyrolysis at 850°C for 1 h, Ag@FeNC is synthesized and demonstrates excellent ORR catalytic activity in alkaline medium. Therefore, it provides a simple method for preparing metal@Fe-N-C hybrid catalysts.

Chains of nickel nanoparticles coated with few nitrogen-doped graphitic carbon layers (Ni@NC) are synthesized by hydrogen-assisted pyrolysis of Ni-ZIF. Hydrogen and temperature can play key roles in the formation of oriented Ni@NC nanoparticle chains, and carbon shells can protect Ni nanoparticles from external oxidation and aggregations. Under the optimized potential (0.60 V vs. Ag/AgCl), the Ni@NC7H nanoparticle chains obtained at 700 °C under H

Background Gout is initiated by the precipitation of monosodium urate (MSU) crystals within the joints and soft tissues, and it can eventually cause acute or chronic arthritis. MSU crystals trigger, amplify, and maintain a strong inflammatory response through promoting proinflammatory activity. In this study, the therapeutic effects of Stephania hainanensis (S. hainanensis) total alkaloid (SHA) were tested and evaluated on MSU-induced acute gouty arthritis in a mouse model. Methods After oral administration of SHA (10 or 20 mg/kg) or the antigout medicine colchicine (0.5 mg/kg) once daily for 3 consecutive days, MSU crystals suspended in saline (2.5 mg/50 μl) were intradermally injected into the right paw of the mice. Then, SHA and colchicine were administered for another 2 days. During this period, swelling of the ankle and clinical scores were measured at 12, 24, and 48 h postinjection. After the mice were euthanized, inflammatory cytokine expression and paw tissue inflammation-related gene and protein expression, and a histopathological analysis was performed. Results SHA had obvious therapeutic effects on MSU-induced acute gouty arthritis in mice. SHA alleviated ankle swelling and inhibited the production of cytokines, such as IL-1β and TNF-α. In addition, NLRP3, Caspase-1 and IL-1β, which are activated by MSU were also suppressed by SHA. The histological evaluation showed that SHA relieved the infiltration of inflammation around the ankle. Conclusions These results suggest that SHA is capable of anti-inflammatory activities and may be useful for treating gouty arthritis.

Iron, cobalt, nickel, and nitrogen doped-carbon nanospheres (FeCoNi/N-C) are synthesized by the pyrolysis of globular Fe/Co/Ni-polypyrrole formed through a microemulsion method. The content and ratio of Fe/Co/Ni in N-C can be adjusted by adding different quantities of metal ions in microemulsion. Compared to Fe/N-C, FeCoNi/N-C demonstrates high conductivity, fast mass transport, superior catalytic properties of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The results showed multi-doping can facilitate the combination of metal and nitrogen and sustain their contents in pyrolysis process to improve conductivity and enhance bifunctional activities. According to the density functional theory calculations, co-doping of Co or/and Ni with Fe element on N-C material can help the desorption of *OH into water in ORR and accelerate the transformation of *O to *OOH in OER. Besides, FeCoNiN4 is a dominant contributor to bifunctional activities.

A melt-salt-assisted method is utilized to construct an onion-like hybrid with Co/CoO nanoparticles embedded in graphitic Fe-N-doped carbon shells (Co/CoO@FeNC) as a bifunctional electrocatalyst. The iron-polypyrrole (Fe-PPy) is firstly prepared with a reverse emulsion. Direct pyrolysis of Fe-PPy yields turbostratic Fe-N-doped carbon (FeNC) with excellent oxygen reduction reaction (ORR) electrocatalysis, while the melt salt (CoCl2) mediated pyrolysis of Fe-PPy obtains onion-like Co/CoO@FeNC with a reversible overvoltage value of 0.695 V, largely superior to Pt/C and IrO2 (0.771 V) and other Co-based catalysts reported so far. The ORR activity is mainly due to the graphitic FeNC and further enhanced by Co Nx bonds, whereas the oxygen evolution reaction (OER) activity is principally due to the Co/CoO composite. Concurrently, Co/CoO@FeNC as cathode catalyst enables Zn-air battery with a high open circuit voltage of 1.42 V, a peak power density of 132.8 mW cm−2, a specific capacity of 813 mAh gZn−1, and long-term stability.

Harpin proteins stimulate hypersensitive response (HR) in plants. However, the mechanism by which HR is regulated is not clear. The role of the auxin, indole-3-acetic acid (IAA), in the control of harpin-stimulated HR was investigated. IAA was used to inhibit HR that was stimulated by purified fusion harpin(Xoo) protein in tobacco. Semi-quantitative PCR and qRT-PCR were employed to detect the expression of HR related genes. IAA at 100 μM reversed harpin-induced HR which was inhibited by 500 μM 2,3,5-triiodobenzoic acid (TIBA). Semi-quantitative PCR and qRT-PCR showed the combined application of 100 μM IAA and harpin protein from Xanthomonas oryzae enhanced the expression of HR marker gene, hsr203J, but weakened the expression of the disease-defense gene, chia5. TIBA also decreased the expression of hsr203J but increased the expression of chia5. Thus, the auxin can reverse harpin(Xoo)-induced HR.

Transplantation of bone marrow regenerative cells after 5-Fu treatment in a rat model of focal cerebral ischemia