ChiCTR-RCS-14004539.

Amorphous molybdenum sulfides (a-MoSx) have been demonstrated as economic and efficient hydrogen evolution catalysts for water splitting. Further improvements of their hydrogen evolution reaction (HER) activities could be achieved by coupling them with appropriate electron transfer intermediates via interfacial engineering. In this study, a novel ternary composite electrode comprising PbTe quantum dots (QDs), a-MoSx and TiO2 nanotube arrays (TNAs) was successfully fabricated by a facile combination of successive ionic layer adsorption and reaction (SILAR) and electrodeposition routes. Investigation of the microstructures and electrocatalytic properties of the a-MoSx/PbTe QD/TNA hybrid material show that PbTe QDs can work as electron temporary storage and electron transfer intermediates between the electrocatalyst a-MoSx and electrode-based material TiO2 that significantly lower the impedance of electrode process, enhance the energy band bending at the interface between the electrolyte and electrode surface, and increase the electrochemically active surface area. The electron interphase crossing from a-MoSx to electrolyte and electron transport inside the electrode are greatly strengthened. The ternary PbTe@MoSx/TNA electrode demonstrates lowered onset potential and Tafel slope and superior electrocatalytic activity and cyclic stability towards HER.

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Background:Refractory femoral neck fractures cannot be anatomically reduced by closed traction reduction which may affect fracture healing. We evaluated the biomechanical effects of positive, negative, and anatomic reduction of various degrees of displacement in Pauwels I femoral neck fractures by a finite element analysis.Methods:Five reduction models of Pauwels type I femoral neck fracture were established using the Mimics 17.0 (Materialize, Leuven, Belgia) and Hypermesh 12.0 (Altair Engineering, Troy, MI, USA). According to the degree of fracture displacement, there were three models of positive support, an anatomic reduction model, and a negative 2 mm reduction model. Finite element analysis was conducted using the ABAQUS 6.9 software (Simulia, Suresnes, France). The von Mises stress distribution and the stress peak of internal fixation in different models, the displacement between fracture blocks, and the principal strain of the femoral neck cancellous bone model were recorded under the axial stress of 2100 N.Results:The peak von Mises stress on screw of each model was located at the thread of the screw tip. The peak von Mises stress was the lowest at the tip of the anatomic reduction model screw (261.2 MPa). In the positive 4 mm model, the von Mises stress peak was the highest (916.1 MPa). The anatomic reduction model showed the minimum displacement (0.388 mm) between fracture blocks. The maximum displacement was noted in the positive 4 mm model (0.838 mm). The displacement in the positive 3 mm model (0.721 mm) was smaller than that in the negative 2 mm model (0.786 mm). Among the five models, the strain area of the femoral neck cancellous bone was mainly concentrated around the screw hole, and the area around the screw hole could be easily cut.Conclusions:Compared with negative buttress for femoral neck fracture, positive buttress can provide better biomechanical stability. In Pauwel type I fracture of femoral neck, the range of positive buttress should be controlled below 3 mm as far as possible.