MOF-derived multicomponent Fe2P-Co2P-Ni2P hollow architectures for efficient hydrogen evolution.

In this work, we introduce Fe and Ni into Co-MOF to construct a kind of multicomponent phosphide hollow architecture with walls assembled by nanosheets. The multicomponent nature can enhance the intrinsic catalytic activity, while the sheet-like surface and inter-sheet voids provide a large active area, which is beneficial for electrolyte penetration and gas generation. As expected, the optimized product has catalytic hydrogen evolution reaction (HER) overpotentials of 105 and 161 mV at current densities of 10 and 100 mA cm-2, respectively, and maintained long-term stability for over 100 hours at 10 mA cm-2 current densities.

Scalable fabrication of NiCoMnO4 yolk-shell microspheres with gradient oxygen vacancies for high-performance aqueous zinc ion batteries.

Defect regulation, which enables better charge transfer and capacity retention in manganese-based cathode materials, is the key to the development of rechargeable aqueous zinc-ion batteries. Herein, yolk-shell structured NiCoMnO4-VO with gradient oxygen vacancies are synthesized by spray pyrolysis and ammonia etching. The generation of the yolk-shell structures are regulated by the diffusion rate of ions in the atomized droplets during the nucleation process instead of adding template agent. In addition, the etching effect of ammonia gradually dissolves nickel oxide in the material from the surface to the interior, creating abounding gradient oxygen vacancies and thereby achieving more active sites for zinc storage and faster charge transfer. Therefore, the material exhibits superior electrochemical performances with initial discharge capacities of 277.9 mA h g-1 at 0.2 A g-1, and the long-term capacities retention rate is 89.3% after 2800 cycles at 5 A g-1. Ex-situ XRD demonstrates NiCoMnO4-VO belongs to the embedding-extraction mechanism of H+ and Zn2+. In-situ optical microscopy reveals that the formation of zinc dendrites is suppressed to some extent.

Synergistic melamine intercalation and Zn(NO3)2 activation of N-doped porous carbon supported Fe/Fe3O4 for efficient electrocatalytic oxygen reduction.

Developing inexpensive, efficient and good stability transition metal-based oxygen reduction reaction (ORR) electrocatalysts is a research topic of great concern in the commercial application of fuel cells. Herein, with zinc nitrate as activator, iron nitrate as active component and melamine as intercalating agent and nitrogen source, an N-doped porous carbon supported Fe/Fe3O4 (Fe/Fe3O4@NC) catalyst is successfully synthesized by an impregnation-calcination method combined with freeze-drying technique. The positive onset potential (E onset), half-wave potential (E 1/2) and limiting current density (J L) of the optimal Fe/Fe3O4@NC catalyst are 1.012, 0.90 V vs. RHE and 5.87 mA cm-2, respectively. Furthermore, Fe/Fe3O4@NC catalyzes ORR mainly through a 4e- pathway, and the yield of H2O2 is less than 5%. It also manifests a robust stability after 5000 CV cycles of ADT testing, and the half-wave potential is only negatively shifted 17 mV. The structural characterization and experimental results further suggest that the outstanding ORR electrocatalytic performance of the Fe/Fe3O4@NC catalyst benefits from the synergetic effect of zinc nitrate activation and nitrogen doping, which can greatly improve the specific surface area, thus better dispersing more metal active sites. This work puts forward a simple and practicable way for preparing high-performance non-noble metal-based biomass ORR electrocatalysts.

Hexamethylenetetramine induced multidimensional defects in Co2P nanosheets for efficient alkaline hydrogen evolution.

Crystal engineering is an important way to improve the catalytic performance of transition-metal phosphides. In this work, we propose a strategy for constructing multi-dimensional defects induced by hexamethylenetetramine, which effectively introduces grain boundaries, N doping and P vacancies into Co2P nanosheets, and improves the activity and stability of the catalyst. Due to the synergistic effect of the multi-dimensional defects, the Co2P nanosheets exhibit excellent HER catalytic performance, especially at a large current density of 100 mA cm-2 with an overpotential of only 159 mV. Under 1 M KOH electrolyte and current density of 10 mA cm-2, the long-term test for 36 h shows that the catalyst maintains a very high stability.

Amplitude of sensory nerve action potential in early stage diabetic peripheral neuropathy: an analysis of 500 cases.

Early diagnosis of diabetic peripheral neuropathy is important for the successful treatment of diabetes mellitus. In the present study, we recruited 500 diabetic patients from the Fourth Affiliated Hospital of Kunming Medical University in China from June 2008 to September 2013: 221 cases showed symptoms of peripheral neuropathy (symptomatic group) and 279 cases had no symptoms of peripheral impairment (asymptomatic group). One hundred healthy control subjects were also recruited. Nerve conduction studies revealed that distal motor latency was longer, sensory nerve conduction velocity was slower, and sensory nerve action potential and amplitude of compound muscle action potential were significantly lower in the median, ulnar, posterior tibial and common peroneal nerve in the diabetic groups compared with control subjects. Moreover, the alterations were more obvious in patients with symptoms of peripheral neuropathy. Of the 500 diabetic patients, neural conduction abnormalities were detected in 358 cases (71.6%), among which impairment of the common peroneal nerve was most prominent. Sensory nerve abnormality was more obvious than motor nerve abnormality in the diabetic groups. The amplitude of sensory nerve action potential was the most sensitive measure of peripheral neuropathy. Our results reveal that varying degrees of nerve conduction changes are present in the early, asymptomatic stage of diabetic peripheral neuropathy.

Encapsulation of gold nanoparticles by simian virus 40 capsids.

Viral capsid-nanoparticle hybrid structures constitute a new type of nanoarchitecture that can be used for various applications. We previously constructed a hybrid structure comprising quantum dots encapsulated by simian virus 40 (SV40) capsids for imaging viral infection pathways. Here, gold nanoparticles (AuNPs) are encapsulated into SV40 capsids and the effect of particle size and surface ligands (i.e. mPEG and DNA) on AuNP encapsulation is studied. Particle size and surface decoration play complex roles in AuNP encapsulation by SV40 capsids. AuNPs ≥15 nm (when coated with mPEG750 rather than mPEG2000), or ≥10 nm (when coated with 10T or 50T DNA) can be encapsulated. Encapsulation efficiency increased as the size of the AuNPs increased from 10 to 30 nm. In addition, the electrostatic interactions derived from negatively charged DNA ligands on the AuNP surfaces promote encapsulation when the AuNPs have a small diameter (i.e. 10 nm and 15 nm). Moreover, the SV40 capsid is able to carry mPEG750-modified 15-nm AuNPs into living Vero cells, whereas the mPEG750-modified 15-nm AuNPs alone cannot enter cells. These results will improve our understanding of the mechanisms underlying nanoparticle encapsulation in SV40 capsids and enable the construction of new functional hybrid nanostructures for cargo delivery.