ABSTRACT
Metallic atoms within metal-organic framework (MOF) materials exhibit a distinctive and adaptable coordination structure. The three-dimensional (3D) pore configuration of MOFs enables the complete exposure of metal active sites, rendering them prevalent in various catalytic reactions. In this study, zinc (Zn) atoms within Zn-based MOF materials, characterized by an abundance of valence electrons, are utilized for the transesterification of dimethyl carbonate (DMC). Additionally, the introduction of zirconium (Zr) effectively addresses the susceptibility of the MOFs' crystal structure to dissolution in organic solvents. The formulated catalyst, Zn-10%Zr-MOF(300), demonstrates remarkable catalytic performance with 91.5% DMC selectivity, 61.9% propylene carbonate (PC) conversion, and 56.6% DMC yield. Impressively, the catalyst maintains its high performance over five cycles. Results indicate that Zr interacts with Zn, forming new coordination bonds and enhancing the catalyst crystal structure stability. Moreover, electron transfer intensifies the alkalinity of the active Zn atoms, enhancing the overall catalyst performance. This research informs the development of transesterification heterogeneous catalysts and broadens the application scope of MOF catalysts.
ABSTRACT
Objective: To explore the risk factors and surgical strategies of knee traumatic arthritis after internal plate fixation in the treatment of tibial plateau fracture. Methods: A total of 300 patients with tibial plateau fractures treated with internal plate fixation in our hospital from January 2019 to April 2021 were retrospectively analyzed. According to whether secondary knee traumatic arthritis occurred after operation, they were divided into control group and research group. The control group was nonsecondary knee traumatic arthritis (n = 231), and the research group was secondary knee traumatic arthritis (n = 69). Univariate and multivariate logistic regression analysis was used in this research. Results: There were significant differences in fracture classification, injury method, osteoporosis, and the time from injury to operation between the two groups, and there are statistically significant differences between groups (P < 0.05). Fracture type, injury method, osteoporosis, and time from injury to operation were the influencing factors of tibial internal fixation, and there are statistically significant differences between groups (P < 0.05). Platform fracture was an independent risk factor for postoperative knee joint traumatic arthritis, and there are statistically significant differences between groups (P < 0.05). The HSS scores of both groups increased after operation, and there are statistically significant differences between groups (P < 0.05). No loosening of the prosthesis was found in all 69 patients with postoperative X-ray examination. Conclusion: Fracture classification, injury mode, osteoporosis, and time from injury to operation are independent risk factors for knee traumatic arthritis in the treatment of tibial plateau fractures with internal plate fixation, incidence of knee trauma.
