Doping-driven electronic structure and conductivity modification of nickel sulfide.

The lack of electrical conductivity limits the electrochemical kinetic rate of the electrode material, resulting in the inability to reach its theoretical capacity. A facile method is adopted to improve the intrinsic conductivity of binary NiS2/Ni3S4 hybrid nickel sulfide, with the doping of transition metal atoms Co, Mn and Ag. Through the introduction of heteroatoms, the electronic structure of the electrode material is modified and the electrical conductivity is significantly improved, thus enhancing its electrochemical performance. The improvement of conductivity is attributed to the formation of intermediate bands of transition metals and the redistribution of electrons, and the result is demonstrated by experimental and density functional theory (DFT) calculations. As a result, the NiS2/Ni3S4 hybrid nickel sulfide after 0.5% amount of Co-doping reaches the highest specific capacitance of 2874 F g-1 at 1 A g-1, increasing specific capacitance of 653 F g-1 as 29.4% of the specific capacitance of non-doped nickel sulfide. The Co doped nickel sulfide also exhibits remarkable cycling stability compared with non-doped nickel sulfide. The assembled 2% Co-doped nickel sulfide//rGO, 0.5% Mn-doped nickel sulfide//rGO and 0.5% Ag-doped nickel sulfide//rGO asymmetric supercapacitors show a specific energy density of 36.6, 36.1 and 36.0 W h kg-1 at a power density of 800 W kg-1. This study provides a useful insight into the fabrication of high performance pseudocapacitive materials.

Internal Versus External Fixation for the Treatment of Distal Radial Fractures: A Systematic Review of Overlapping Meta-Analyses.

Although a serious of meta-analyses have been published to compare the effects of internal versus external fixation (IF vs EF) for treating distal radial fractures (DRF), no consensus was obtained.B y performing a systematic review of overlapping meta-analyses comparing IF versus EF for the treatment of distal radial fractures, we attempted to evaluate the methodology and reporting quality of these meta-analyses, interpret the source of discordant results, and therefore determine the dominant strategy for the treatment of distal radial fractures based on the best evidence currently. An electronic databases search was conducted in MEDLINE, Embase, and Cochrane library to retrieve meta-analyses comparing IF versus EF for treating DRF. Reference lists of relevant literatures were also screened manually to retrieve additional ones. Two investigators independently assessed the eligibility of retrieved articles using predefined inclusion and exclusion criteria. All characteristics as well as outcome variables including functional outcomes, range of motion, radiological results, and complication rates with relevant heterogeneity information presented in each included study were extracted. Heterogeneity was thought to be significant when I²â€Š> 50%. We adopted the Oxford Levels of Evidence and the Assessment of Multiple Systematic Reviews (AMSTAR) Instrument to assess the methodological quality of every included study, and applied the Jadad decision algorithm to select studies with more likely reliable conclusions. A total of 8 studies met the inclusion criteria. The AMSTAR scores ranged from 5 to 9 with a median of 7.75. Following the Jadad algorithm, the meta-analyses with most reliable results can be selected based on the search strategies and application of selection. Finally, 2 meta-analyses with most RCTs and highest AMSTAR scores were selected in this systematic review of overlapping meta-analysis. The best available evidence suggested that compared with EF, IF was significantly associated with lower Disabilities of the Arm, Shoulder and Hand (DASH) scores, better rehabilitation of volar tilt and radial inclination, and lower infection rate at 1-year follow-up. Therefore, we could conclude that internal fixation is superior to external fixations for the treatment of distal radial fractures.