Design of a new Li-rich Mn-based ternary cathode material based on the Ni, Co, and Mn action mechanism.

Rechargeable lithium-ion batteries, as the most advanced energy storage devices currently available, urgently require the development of cathode materials with high capacity, large specific energy, and fast charge/discharge performance to satisfy the continuous technological innovation. Here, a Li-rich Mn-based ternary cathode material Li7/6Nil/6Co1/6Mn1/2O2 is designed, and the geometrical structure, electronic properties, and thermodynamic properties of this material are investigated employing the first-principles method. Six layered structure models are established by adjusting the ratio of Ni, Co, and Mn elements, and the effects of various elements on the material properties are evaluated. Based on the performance of Ni, Co, and Mn in the structure, Li1.2Ni0.15Co0.1Mn0.55O2 features favorable electrical conductivity, thermal conductivity, and excellent stability. This material obtained through co-precipitation using a high temperature solid phase synthesis presents a high actual capacity (245 mA h g-1) and superior cycling performance (the capacity retention rate of the material is 84% after 60 cycles at 0.2C). This effort discusses the Li-rich Mn-based cathode materials in terms of the structural basis, reaction mechanism, and application exploration, which are valuable for guiding their theoretical design, optimization modification, and industrial application.

[Clinical application of targeted sealing with high viscosity bone cement and secondary injection of low viscosity bone cement in vertebroplasty].

OBJECTIVE: To observe the clinical efficacy of targeted sealing with high viscosity bone cement and secondary injection of low viscosity bone cement in the treatment of OVCFs patients with the fracture lines involved vertebral body margin. METHODS: The elderly patients who underwent vertebroplasty for osteoporotic vertebral compression fractures from January 2019 to September 2021 were selected as the screening objects. Through relevant standards and further CT examination, 56 patients with fracture lines involving the anterior wall or upper and lower endplates of the vertebral body were selected for the study. There were 21 males and 35 females, aged from 67 to 89 years old with an average of (76.58±9.68) years. All 56 patients underwent secondary injection of bone cement during operation. Only a small amount of high viscosity cement was targeted to seal the edge of the vertebral body for the first time, and low viscosity cement was injected to the vertebral bodies during second bolus with well-distributed. The operation time, bone cement volume and bone cement leakage were recorded, and the pain relief was evaluated by visual analogue scale (VAS). RESULTS: All patients were followed up for more than 3 months and the surgeries were successfully complete. The operation time was (50.41±10.30) min and the bone cement volume was (3.64±1.29) ml. The preoperative VAS was (7.21±2.41) points, which decreased significantly to (2.81±0.97) points 3 days after operation(P<0.05). Among the 56 patients, 2 cases(3.57%) had bone cement leakage, 1 case leaked to the paravertebral vein, and 1 case slightly bulged to the paravertebral through the crack when plugging the vertebral crack. Both patients had no obvious clinical symptoms. CONCLUSION: In vertebroplasty surgery, targeted sealing of high viscosity bone cement and secondary injection of low viscosity bone cement can reduce intraoperative bone cement leakage and improve the safety of operation.

Bidirectional controlling synthesis of branched PdCu nanoalloys for efficient and robust formic acid oxidation electrocatalysis.

Through a two-way control of hexadecyl trimethyl ammonium bromide (CTAB) and hydrochloric acid (HCl), the PdCu nanoalloys with branched structures are synthesized in one step by hydrothermal reduction and used as electrocatalysts for formic acid oxidation reaction (FAOR). In this two-way control strategy, the CTAB is used as a structure-oriented surfactant, while a certain amount of HCl is used to control the reaction kinetics for achieving gradual growth of multi-dendritic structures. The characterizations including scanning transmission electron microscope (STEM), X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) suggest that PdCu nanoalloys with unique multi-dendritic branches have favorable electronic structure and lattice strain for electrocatalyzing the oxidation of formic acid. In specific, among the electrocatalysts with different Pd/Cu ratios, the Pd1Cu1 branched nanoalloys have the largest electrochemically active surface area (ECSA) and the best performance for the FAOR. The catalytic activity of the Pd1Cu1 branched nanoalloys is 2.4 times that of commercial Pd black. After the chronoamperometry test, the Pd1Cu1 branched nanoalloys still maintain their original morphologies and higher current density than that of the commercial Pd black. In addition, in the CO-stripping tests, the initial oxidation potential and the oxidation peak potential of the PdCu branched nanoalloys for CO adsorption are lower than those of commercial Pd balck, evincing their better anti-poisoning performance.

[Application of three-dimensional CT and image classification in percutaneous vertebraplasty for osteoporotic vertebral compression fractures].

OBJECTIVE: To explore the application of three-dimensional CT and image classification in the treatment of osteoporotic vertebral compression fracture(OVCFs) by percutaneous vertebroplasty(PVP). METHODS: A total of 90 patients with OVCFs who were treated with PVP in Linqu People's Hospital of Shandong Province from April 2016 to March 2018 were selected as subjects. There were 31 males and 59 females, aged from 63 to 84 years old. Bone mineral density measurements were performed in all patients to confirm the presence of osteoporosis and imaging examinations were performed to confirm the presence of vertebral fractures. The fracture area was determined by MRI fat surpressed image before operation and three-dimensional modeling was performed to calculate the volume of fracture area. Three dimensional CT imaging of bone cement in fracture area was performed after PVP and the volume ratio of bone cement in fracture area was calculated by computer aided design software, by which patients were divided into groups for study. Forty-one patients whose volume ratio of bone cement in fracture area less than 50% are control group and the rest of 90 patients are observation group. Visual analogue scale (VAS) and Oswestry Disability Index(ODI) were collected in two groups before operation and 1 day, 3 months after operation. The amount of bone cement was recorded after operation. RESULTS: All operations were successful. There were 3 cases of cement leakage in control group and 4 cases in observation group. All patients had no obvious clinical symptoms. After continuous observation and follow-up for 3 months, no complications such as adjacent vertebral fracture, infection, bone cement displacement were found. There was no significant difference in bone cement doses and bone cement leakage between two groups(P>0.05). There was no significant difference in preoperative VAS and ODI between two groups(P>0.05). All VAS and ODI obviously decreased(P<0.05) at 1 day after operation and in observation group the decrease was more significant (P<0.05). At 3 months after operation there was no significant difference between two groups. This may have been due to basically healing of vertebral fractures at 3 months after surgery and the pain was no longer significantly related. CONCLUSIONS: PVP can significantly improve clinical symptoms of OVCFs and bone cement filling in fracture area is the key to the short-term effect of PVP.