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Barium titanate-based microwave dielectrics usually require relatively high temperatures to sinter, which prevents the use of base metals such as copper for electrodes. In this work, BaTi4O9 microwave dielectric ceramics co-fired with copper electrodes are made possible by adding B-Si-Ba- Zn-O glass to induce liquid-phase sintering at sufficiently low temperature and in reduced atmosphere. The microstructures and electric properties of the BaTi4O9 ceramics thus obtained are carefully examined and studied. Proper glass composition may significantly facilitate mass transportation in the low-temperature co-fired ceramic (LTCC) material, resulting in better densification without serious degradation of electric properties. Although the B2O3/SiO2 ratio enhances the glass mobility during sintering, the BaO/ZnO ratio contributes to the chemical affinity of glass to BaTi4O9 ceramics. In addition, various Ba-Ti-O phases with different Ba/Ti ratios may be found in the specimen through the X-ray diffraction patterns when the BaO/ZnO ratio is varied. If the BaO/ZnO ratio is high and the glass flows easily in the material, the Ba4Ti13O30 phase is formed. If the BaO/ZnO ratio is low and the glass flows easily in the material, the BaTi6O13 phase appears. We find that glass-induced Ba4Ti13O30 transformation may significantly decrease Qxf values in the BT4-BSBZ materials. Therefore, the appropriate glass composition must be selected to ensure the phase stability of dielectrics to achieve the best performance possible. [ABSTRACT FROM AUTHOR]

Objectives: To determine the potential risk factors for intraoperative periprosthetic femoral fractures in patients with developmental dysplasia of the hip (DDH) undergoing total hip arthroplasty (THA). Methods: This was a retrospective study. Patients who were diagnosed with DDH and undergoing THA (by artificial joint replacement) at our hospital from January 1999 to December 2019 were included in this study. Clinical and radiological factors were obtained from their medical records, such as age, sex, Crowe classification, morphological features of proximal femur, and features of surgical procedure. The outcome of interest was the occurrence of intraoperative periprosthetic femoral fracture, which was recorded and classified according to the Vancouver classification system. According to the fracture status, the patients were divided into two groups: the fracture group and the non‐fracture group. Multivariate logistic regression model was built to identify the risk factors for these fractures. Results: A total of 1252 hips were finally included. Intraoperative periprosthetic femoral fractures were identified in 62 hips. The incidence of intraoperative periprosthetic femoral fractures in patients with DDH undergoing THA was 4.95%. There were 22 patients (proportion = 35.48%, incidence = 1.76%) with Type A fractures, 38 (proportion = 61.29%, incidence = 3.04%) with Type B fractures, and two (proportion = 3.23%, incidence = 0.16%) with Type C fractures. Six independent risk factors for intraoperative periprosthetic femoral fractures were identified: osteoporosis (OR = 3.434; 95% CI, 1.963–6.007), previous surgical history (OR = 4.797; 95% CI, 2.446–9.410), Dorr Type A canal (OR = 3.025; 95% CI, 1.594–5.738), retained femoral neck length (OR = 1.121; 95% CI, 1.043–1.204), implanted metaphyseal‐diaphyseal fixation stems (OR = 3.208; 95% CI, 1.562–6.591), and implanted stem with anteversion design (OR = 2.916; 95% CI, 1.473–5.770). Conclusions: The overall incidence of intraoperative periprosthetic femoral fractures in patients with DDH undergoing THA was 4.95%, which was at a moderate level compared to patients with other diseases undergoing THA. Six independent risk factors were identified: osteoporosis, previous surgical history, Dorr Type A canal, insufficient neck osteotomy level, implantation of metaphyseal‐diaphyseal fixation stem, and implantation of a stem with an anteversion design. Comprehending these risk factors might help surgeons prevent the occurrence of these intraoperative periprosthetic femoral fractures in patients with DDH. [ABSTRACT FROM AUTHOR]