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This paper introduces a unified and exact method for the vibration solution of three versions of Timoshenko beam theory, namely the classical Timoshenko beam theory (TBT), truncated Timoshenko beam theory (T-TBT), and slope inertia Timoshenko beam theory (S-TBT). The proposed unified method enables the free vibration analysis of these three beam theories performed by only one equation, which avoids separate modeling and solution with different beam theories. Firstly, the comparison of three beam theories is conducted with a special focus on deriving the governing differential equation of T-TBT based on Hamilton's principle. Then, two parameters are introduced to unify the three governing differential equations. The dynamic stiffness matrix is derived in a unified form by reducing the order of inverse matrix operation from 2 n to n, allowing the dynamic properties of three beam theories to be characterized with only a single model. Additionally, this paper also derives the unified frequency-dependent mass and stiffness matrices based on the unified dynamic stiffness matrix, which eliminates the limitation of DSM in studying the independent influence of the structure's mass and stiffness characteristics. Finally, the discrepancies of the three beam theories are discussed under different boundary conditions and aspect ratios. [ABSTRACT FROM AUTHOR]

The performance of aluminum alloys can be affected by the element of magnesium. Therefore, it is necessary to realize fast and accurate quantitative analysis of magnesium in aluminum alloys. Herein, high repetition rate spark discharge assisted laser-induced breakdown spectroscopy based on microchip lasers (HRR SD-LIBS) was applied to quantitatively analyze magnesium elements in aluminum alloys. Baseline correction was performed using the moving median method to obtain the net spectral data. Multivariate calibration models such as back-propagation neural network (BP), support vector machine (SVM), and random forest (RF) were established, respectively. Compared with the conventional univariate calibration model, the correlation coefficients (RP²) of BP,SVM and RF models increased from 0. 810 to 0.985, 0.997 and 0.994, while the root mean square error (RMSEP) decreased from 0.283 to 0.059 8, 0.041 0 and 0.054 2, the average relative error decreased from 26.62% to 3.13%, 2.82%, and 3.61%. It indicated that machine earning combined microchip laser-based HRR SD-LIBS significantly improved the quantitative analysis ability of LIBS. In conclusion, it is promising to achieve portable, fast, and accurate quantitative elemental analysis of alloy sample and other materials. [ABSTRACT FROM AUTHOR]

Syringoma is a common but refractory benign skin tumor. Conventional treatment, such as ultra‐pulsed carbon dioxide (CO2) laser or cryotherapy, often requires multiple treatment and can easily cause prolonged erythema, scarring, or depression, which are frustrating, so there is an urgent need to seek a safer and more effective method. In this article, we tried to demonstrate the Er:YAG laser combined with botulinum toxin A (BTXA) as a safer and more efficacious method for treating syringomas. Materials and methods: Twenty‐one patients with local syringomas were treated with erbium laser ablation. Immediately after laser treatment, approximately 10 units of BTXA were sprayed on the wound for 10 min. Result: In total, 21 patients underwent 1.62 ± 0.74 treatments; their Periorbital Syringoma Severity Index (PSSI) score declined from 4.19 (before treatment) to 1.10 (after treatment), and the number of treatments was significantly lower than those reported in previous literature using the erbium laser alone. Conclusion: The Er:YAG laser combined with botulinum toxin A for the treatment of syringoma is a safer and more effective treatment than traditional treatment methods. [ABSTRACT FROM AUTHOR]

Stability prediction of the securing system for autonomous trucks is an important prerequisite for achieving safety monitoring of large cargo transportation and improving logistics efficiency. Considering the side slide risk of large cargo and the inability to predict stability using the existing under-constrained friction securing model, this paper proposes a new vehicle–cargo securing model based on the 6-SPS parallel mechanism. By establishing an analytical 3-DOF model, the dynamics performance of the vehicle–cargo system is analyzed based on the response solution under sinusoidal excitations. To verify the correctness of the analytical model, a multi-body dynamics model of the whole vehicle–cargo system based on the three-dimensional geometric model and the 6-SPS parallel mechanism is established for simulation in ADAMS. According to road class, pavement roughness is modeled by a white noise power spectrum method as the excitation in the simulation. The results show that the dynamics response of the analytical model accords well with that of the simulation model, with relative errors of 8.34% and 0.036% in amplitude and frequency, respectively. The proposed method can provide theoretical support for accurate stability prediction and for achieving safety monitoring of large cargo transportation for autonomous trucks. [ABSTRACT FROM AUTHOR]

Current treatments do not support direct exposure of fracture fragments, resulting in the inability to directly observe the articular surface during surgery for accurate reduction and firm fixation. The aim of the study was to explore the treatment effect of digital virtual reduction combined with individualized guide plate of lateral tibial condyle osteotomy on tibial plateau fracture involving the lateral posterior condyle collapse. 41 patients with tibial plateau fracture involving the lateral posterior condyle collapse were recruited in the trial. All patients underwent Computed Tomography (CT) scanning before operation. After operation, fracture reduction was evaluated using Rasmussen score and function of knee joint was assessed using hospital for special surgery (HSS) score. 41 patients were followed-up 6–26 months (mean, 15.2 months). Fracture reduction was good after operation, with an average of 13.3 weeks of fracture healing without serious complications. The excellent and good rate was 97.6%. The joint movement degree was -5∘∼0∘∼135∘ with an average of 125.5∘. Digital virtual reduction combined with individualized guide plate of lateral tibial condyle osteotomy was effectively for treating tibial plateau fracture involving the lateral posterior condyle collapse. [ABSTRACT FROM AUTHOR]

Background: The impact of remifentanil on hypogastric flap function following ischemia-reperfusion (I/R) injury remains largely unknown, limiting its potential clinical application in flap surgery. This study investigated the therapeutic effects of remifentanil on hypogastric flap I/R injury., Methods: Aortic endothelial cells were extracted from the hypogastric flap I/R injury models established in-house using Sprague-Dawley rats, and were treated under hypoxic conditions. The cells were treated with 0.1, 1, 10 and 100 ng/mL remifentanil and 10 ng/mL anisomycin (the activator of c-Jun N-terminal kinase [JNK]). Histopathological changes and tumor necrosis factor alpha (TNF-α) content of the flaps were observed after hematoxylin-eosin staining and immunohistochemistry. Immunofluorescence, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining and flow cytometry were employed for apoptosis evaluation. Western blotting, quantitative real-time polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA) were utilized to assess the protein and gene expression levels of TNF receptor 1 ( TNFR1 ), JNK1 , phosphorylated (p)-JNK1, malondialdehyde (MDA), superoxide dismutase (SOD), nitric oxide (NO) and TNF-α in the flaps and cells., Results: The endothelial necrosis and cell apoptosis of rat flaps induced by I/R injury were ameliorated by remifentanil, and declining aortic endothelial cell viability and augmented apoptosis induced by hypoxia were reversed by remifentanil (10, 100 ng/mL) ( p < 0.05). Remifentanil reversed the increased expressions of TNFR1 , JNK1 , p-JNK1, MDA and TNF-α induced by I/R injury or hypoxia in the flaps and cells ( p < 0.05), and counteracted the decreased levels of NO and SOD induced by I/R injury in the flaps ( p < 0.05). Anisomycin reversed the effects of remifentanil on suppressing TNFR1 , JNK1 and p-JNK1 levels and apoptosis in the cells ( p < 0.05)., Conclusion: Remifentanil ameliorates cell apoptosis and vascular endothelial necrosis induced by I/R injury in the hypogastric flap, likely by downregulating the TNF-α/TNFR1 pathway and JNK1 signaling. These findings suggest that remifentanil may be a promising therapeutic agent for improving hypogastric flap survival in clinical settings.

Objective: To introduce a locating device for the entry point of intramedullary nail based on the inertial navigation technology, which utilizes multi-dimensional angle information to assist in rapid and accurate positioning of the ideal direction of femoral anterograde intramedullary nails' entry point, and to verify its clinical value through clinical tests., Methods: After matching the locating module with the developing board, which are the two components of the locating device, they were placed on the skin surface of the proximal femur of the affected side. Anteroposterior fluoroscopy was performed. The developing angle corresponding to the ideal direction of entry point was selected based on the X-ray image, and then the yaw angle of the locating module was reset to zero. After resetting, the locating module was combined with the surgical instrument to guide the insertion angle of the guide wire. The ideal direction of entry point was accurately located based on the angle guidance. By setting up an experimental group and a control group for clinical surgical operations, the number of guide wire insertion times, surgical time, fluoroscopy frequency, and intraoperative blood loss with or without the locating device was recorded., Results: Compared to the control group, the experimental group showed significant improvement in the number of guide wire insertion times, surgical time, fluoroscopy frequency, and intraoperative blood loss, with a statistically significant difference ( P <0.01)., Conclusion: The locating device can assist doctors in quickly locating the entry point of intramedullary nail, effectively reducing the fluoroscopy frequency and surgical time by improving the success rate of the guide wire insertion with one shot, improving surgical efficiency, and possessing certain clinical value.

Microplastics (MPs) have been detected in many ecosystems, such as the ocean, land and the atmosphere. A large number of MPs in urban sewage are trapped in the activated sludge by sewage treatment plants, but tens of thousands of MPs 'escape' the treatment and are discharged into the nature. Meanwhile, most of the MPs are transferred into the activated sludge during sewage treatment, and the sludge will be further used in agriculture, leading to secondary pollution of the MPs. Through literature research, we summarized the sources, distribution and hazards of MPs in the environment, the treatment of MPs with activated sludge, and the treatment methods of residual MPs in activated sludge, and summed up the potentials of biotechnology and synthetic biology in the genetic modification of key bacteria in activated sludge to endow them with MPs-degrading ability. The conclusion is expected to serve as a reference for optimizing the biodegradation of MPs in wastewater treatment plants.