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In this paper, an analytical model of a rotor-bearing-rotor coupling system is established for aero-engine from the Lagrange equation, based on the dynamics theory of the dual-rotor system and combined with its stiffness, damping, and misalignment characteristics. In the model, the misalignment fault simulation method is introduced. The coupling effect between the low-pressure rotor and high-pressure rotor and the influence of misalignment of the support on low-pressure coupling are considered. The vibration characteristics of the dual-rotor system with the misalignment fault of the low-pressure turbine rear support are studied. The time-domain responses, the frequency spectra, and the shaft-center trajectory of the dual-rotor system with different misalignments are obtained. The influence of unbalance on the vibration characteristics of the low-pressure rotor and the high-pressure rotor with misalignment fault is analyzed. Finally, test verification is carried out by the designed dual-rotor test rig. The experimental results are consistent with the analytical results, confirming the established model's feasibility and simulation method in this paper. The results may provide a theoretical basis for research on the misalignment fault in aero-engine dual-rotor systems.

Aims/Background Patients receiving treatment in specialized cancer hospitals are particularly susceptible to multidrug-resistant organisms (MDRO) infections due to factors such as weakened immune systems caused by intensive treatments and prolonged hospital stays. This study aims to investigate the risk factors for MDRO infections in the cancer specialty hospital setting and to develop a corresponding risk prediction model. Methods Patients diagnosed with MDRO infections were selected for the MDRO infection group (n = 238), and those without for the non-MDRO infection group (n = 238). Non-parametric tests, chi-square tests, and multivariate logistic regression analysis were used to identify the primary risk factors for MDRO infections. With the aid of analysis utilizing R software 4.4.1 (R Foundation for Statistical Computing, Vienna, Austria), we developed a nomogram prediction model, which was evaluated using the receiver operating characteristics (ROC) curve, calibration curve, and decision curve analysis (DCA). Results Age, antibiotic application time, and central venous catheterization were independent risk factors for MDRO infection (p < 0.05). The constructed nomogram prediction model for patients with MDRO infection has a C-index of 0.8640. The ROC curve results showed that the prediction model has a specificity of 0.7700, a sensitivity of 0.8800, and an area under the curve (AUC) of 0.8800. Conclusion This study identifies significant risk factors for MDRO infections in a cancer specialty hospital setting and offers a clinically useful prediction model, which may aid in targeted preventive measures and optimization of antibiotics usage, thereby potentially reducing the incidence and impact of these infections. [ABSTRACT FROM AUTHOR]

A high sodium (HS) diet is believed to affect bone metabolism processes. Clarifying its impact on osseointegration of titanium (Ti) implants holds significant implications for postoperative dietary management of implanted patients. This investigation probed the impact of sodium ions (Na+) on neovascularization and osteogenesis around Ti implants in vivo , utilizing micro-computed tomography, hematoxylin and eosin staining, and immunohistochemical analyses. Concurrently, in vitro experiments assessed the effects of varied Na+ concentrations and exposure durations on human umbilical vein endothelial cells (HUVECs) and MC3T3-E1 cells. In vivo , increased dietary sodium (0.8%–6.0%) led to a substantial decline in CD34 positive HUVECs and new bone formation around Ti implants, alongside an increase in inflammatory cells. In vitro , an increase in Na+ concentration (140–150 mmol/L) adversely affected the proliferation, angiogenesis, and migration of HUVECs, especially with prolonged exposure. While MC3T3-E1 cells initially exhibited less susceptibility to high Na+ concentrations compared to HUVECs during short-term exposure, prolonged exposure to a HS environment progressively diminished their proliferation, differentiation, and osteogenic capabilities. These findings suggest that HS diet had a negative effect on the early osseointegration of Ti implants by interfering with the process of postoperative vascularized bone regeneration. [ABSTRACT FROM AUTHOR]