Significant Change of Metal Cations in Geometric Sites by Magnetic-Field Annealing FeCo2 O4 for Enhanced Oxygen Catalytic Activity.

The application of magnetic fields in the oxygen reduction/evolution reaction (ORR/OER) testing for electrocatalysts has attracted increasing interest, but it is difficult to characterize on-site surface reconstruction. Here, a strategy is developed for annealing-treated FeCo2 O4 nanofibers at a magnetic field of 2500 Oe, named FeCo2 O4 -M, showing a right-shifted half-wave potential of 20 mV for the ORR and a left-shifted overpotential of 60 mV at 10 mV cm-2 for the OER as compared with its counterpart. Magnetic characterizations indicate that FeCo2 O4 -M shows the spin-state transition of cations from a low-spin state to an intermediate-spin state compared with FeCo2 O4 . Mössbauer spectra show that the Fe3+ ion in the octahedral site (0.76) of FeCo2 O4 -M is more than that of FeCo2 O4 (0.71), indicating the effective stimulus of metal cations in geometric sites by magnetic-field annealing. Furthermore, theoretical calculations demonstrate that the d-band centers (εd ) of Co 3d and Fe 3d in the tetrahedral and octahedral sites of the FeCo2 O4 -M nanofibers shift close to the Fermi level, revealing the enhanced mechanism of the ORR/OER activity.

Relationship between plasma homocysteine and chronic kidney disease in US patients with type 2 diabetes mellitus: a cross-sectional study.

AIMS: This cross-sectional study aimed to investigate the association between plasma homocysteine (Hcy) and chronic kidney disease (CKD) in US patients with type 2 diabetes mellitus (T2DM). METHODS: We used data from the 2003-2006 National Health and Nutritional Examination Surveys (NHANES). CKD was defined as an estimated glomerular filtration rate < 60 ml/min/1.73 m2 and/or urinary albumin-creatine ratio ≥ 3 mg/mmol. RESULTS: This study included 1018 patients with T2DM. The mean Hcy value was 10.2 ± 4.6 µmol/L. Among the patients, 417 (40.96%) had hyperhomocysteinemia (HHcy) and 480 (47.15%) had CKD. The Hcy level was higher in patients with CKD than in those without CKD. Compared to patients with normal Hcy, those with HHcy were older and had worse renal function. After full multivariate adjustment, HHcy was positively associated with the risk of CKD in US patients with T2DM (OR, 1.17; 95% CI, 1.11-1.22; P <  0.001), which for women was 1.15 (95% CI, 1.08 ~ 1.23; P <  0.001) and for men was 1.18 (95% CI, 1.1 ~ 1.27; P <  0.001). CONCLUSIONS: HHcy was independently associated with CKD in patients with T2DM. Further prospective studies are warranted to investigate the effect of Hcy on CKD in patients with T2DM.

Co and CeO2 co-decorated N-doping carbon nanofibers for rechargeable Zn-air batteries.

The heterogeneous Co and CeO2 co-decorated N-doping carbon nanofibers (Co-CeO2-N-C) were synthesized via the electrospinning technique. As the bifunctional electrocatalyst, Co-CeO2-N-C nanofibers show excellent oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) performance, owing to the higher degree of graphitization of carbon, the N-doping, and the formation of an interface between Co and CeO2. The liquid Zn-air battery based on Co-CeO2-N-C nanofibers displays excellent specific capacities (815.9 mA h g-1 at 5 mA cm-2), higher open circuit voltages (1.47 V), and good cycling stability (113 h). The corresponding flexible solid state Zn-air battery shows excellent cycling stability (11 h), and good flexibility. Our finding suggests that Co-CeO2-N-C nanofibers could serve as a new group of bifunctional electrocatalysts for OER and ORR with excellent performance, and make them promising for use in future electric vehicles, off-grid power sources, and portable electronics.

One-Step Electrospinning Method to Prepare Gold Decorated on TiO2 Nanofibers with Enhanced Photocatalytic Activity.

A gold doped titanium dioxide (TiO2) nanofiber was prepared by one-step electrospinning technique to control the DC high voltage and the following calcination. The crystal structures and morphology of Au-TiO2 nanofibers were characterized in detail by X-ray diffraction (XRD), energy dispersive photoelectron spectroscopy (EDS), scanning electron microscope (SEM) and transmission electron microscope (TEM). These results indicate that Au is successfully incorporated into TiO2 nanofibers without gold loss, while Au and TiO2 form a heterogeneous structure. It implied that the Schottky barrier existed by X-ray photoelectron spectroscopy (XPS) of 0.075% Au-TiO2. For 0.075% Au-TiO2 nanofibers, the rate of photocatalytic degradation of methylene (MB) was significantly higher than that of pure TiO2 nanofibers.

Efficient electrocatalyst of α-Fe2O3 nanorings for oxygen evolution reaction in acidic conditions.

Large-scale application of sustainable energy devices urgently requires cost-effective electrocatalysts to overcome the sluggish kinetics related to the oxygen evolution reaction (OER) under acidic conditions. Here, we first report the highly efficient electrocatalytic characteristics of α-Fe2O3 nanorings (NRs), which exhibits prominent OER electrocatalytic activity with lower overpotential of 1.43 V at 10 mA cm-2 and great stability in 1 M HCl, surpassing the start-of-the art Ir/C electrocatalyst. The significantly optimized OER activity of the α-Fe2O3 NRs mainly attributes to the synergistic effect of the excellent electrical conductivity and a large effective active surface because of their unique nanoring structure, disordered surface, and the dynamic stability of α-Fe2O3 NRs in acidic conditions.

Interfacial Engineering of NiO/NiCo2O4 Porous Nanofibers as Efficient Bifunctional Catalysts for Rechargeable Zinc-Air Batteries.

To meet the crucial demand of regenerative Zn-air (ZA) batteries, low cost, highly efficient, and durable electrocatalysts for the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are needed to replace the noble metal. Herein, porous NiO/NiCo2O4 nanofibers with superior electrocatalytic performance are synthesized by a facile electrospinning strategy with precursor transition metal salts in nonstoichiometric ratio, which confers the heterostructured NiO/NiCo2O4 with abundant interface-related active sites and electronic transmission channels. Density functional calculation results reveal the chemical bonds easily form between NiO and NiCo2O4 to facilitate the charge transfer, while X-ray absorption fine spectroscopy and X-ray photoelectron spectroscopy results demonstrate there are abundant Ni3+ and Co3+ species in NiO/NiCo2O4 due to the interfacial engineering. As a result, the NiO/NiCo2O4 porous nanofibers exhibit highly efficient and durable performances of OER and ORR in KOH solution, including a lower overpotential of 357 mV at 10 mA cm-2 (OER) and half-wave potential of 0.73 V (ORR) than that of the individual. What's more, the NiO/NiCo2O4-based ZA battery displays excellent specific capacities of 814.4 mA h g-1, and good cycling stability of 175 h. Additionally, the flexible ZA battery displays a long cycling life of 14 h and decent flexibility. This work shows that construction of the heterostructure could provide a feasible method to optimize their electrocatalytic performance and make them widely used in power source devices.

Durable oxygen evolution reaction of one dimensional spinel CoFe2O4 nanofibers fabricated by electrospinning.

One dimensional spinel CoFe2O4 nanofibers were synthesized via the electrospinning technique. The nanofibers were calcined at different temperatures. All CoFe2O4 nanofibers show excellent oxygen evolution reaction (OER) performance. The nanofibers calcined at 750 °C have a multi-particle nanochain structure. The nanochain exhibits excellent catalytic performance for OER in 1 M KOH (pH = 14) producing a current density of 10 mA cm-2 at an overpotential of 0.34 V, and the small onset potential of 1.32 V versus RHE, better than that of the commercial Ir/C (20%) catalyst. Furthermore, the stability of CoFe2O4 multi-particle nanochains toward the OER decreases by only 0.78% even after a long period of 80 000 s. Our finding suggests that CoFe2O4 nanofibers with a multi-particle nanochain structure could serve as a new group of OER electrocatalysts with excellent performance.

Myeloid-derived suppressor cells protect mouse models from autoimmune arthritis via controlling inflammatory response.

Myeloid-derived suppressor cells (MDSCs) have been reported to participate in immune suppression and autoimmune disorders. However, its role in autoimmune arthritis remains to be determined. We explored whether adoptive transfer of MDSCs in vivo would block joint inflammation and histological damage using collagen-induced arthritis (CIA) and antigen-induced arthritis (AIA) models. CD11b(+) Gr-1(+) MDSCs were isolated from the single cells from the spleens of CIA mice on day 41 or AIA mice on day 35. MDSCs (2 × 10(6)) were then transferred to AIA and CIA mice via tail vein before arthritis establishment at indicated time points. Phosphate buffered saline (PBS) was injected as control. Arthritis was evaluated by severity score and histology. The levels of TNF-α, IL-6, IL-17 and IL-10 in the serum and joints were detected by enzyme-linked immunosorbent assay (ELISA). The number of Th17 cells and macrophages in draining lymph nodes and joint tissues was assessed by flow cytometric analysis. Adoptive transfer of MDSCs significantly reduced the clinical score of arthritis, alleviated joint inflammation and histological damage both in AIA and CIA models compared with PBS-treated control groups. The levels of TNF-α, IL-6, IL-17, and IL-10 in the serum and joints were down-regulated by transfer of MDSCs. In addition, adoptive transfer of MDSCs significantly reduced the number of Th17 cells and macrophages in draining lymph nodes and joint tissues. Altogether, we demonstrate that adoptive transfer of MDSCs prevented autoimmune arthritis in mouse models of RA through inhibiting Th17 cells and macrophages. These new findings provide insights into the inhibitory functions of MDSCs and MDSCs may be used as a cell-based biotherapy in RA.