Search

Steel-concrete composite slabs are vital structural components in engineering facilities, exhibiting high shear strength, stiffness, and energy dissipation capabilities. However, few studies have examined steel-concrete composite slabs subjected to underwater explosions. This study compared the dynamic response and damage characteristics of single-side steel-concrete composite slabs, steel-concrete-steel composite slabs, and reinforced concrete slabs subjected to underwater near-field explosions through experiments. The results indicated that bubble loading exacerbated specimen damage beyond shock wave loading alone, highlighting its significance. Each specimen exhibited distinct damage patterns, including crack distribution, concrete crushing, spalling, and localized damage. Compared with single-side steel-concrete composite slabs and reinforced concrete slabs, steel-concrete-steel composite slabs exhibited the weakest dynamic response, with maximum displacement reduced by 53% and 38%, respectively. Furthermore, they exhibited superior integrity after the blast, exhibiting excellent anti-explosion performance. These research results offer valuable insights for the explosion-resistant design of underwater engineering structures. [ABSTRACT FROM AUTHOR]

Due to the characteristics of geographical environment and many complicated factors, the seepage properties of calcareous sand are quite different from those of common continental and marine sediments. To investigate the change of permeability coefficient of calcareous sand under external load, a seepage test device equipped with an impact loading system was developed. The effects of particle size distribution, initial relative density and impact load on the permeability of calcareous sand were investigated with this device. The results showed that the larger the curvature coefficient and uniformity coefficient, the smaller the initial relative density lead to the greater the permeability coefficient of calcareous sand and the more obvious the change of permeability coefficient before and after loading. The permeability change of calcareous sand under impact load was greater than that of quartz sand. [ABSTRACT FROM AUTHOR]

The prominent performance of wave elimination and energy absorption makes calcareous sand important and useful in infrastructure construction and protection engineering. Due to the high compressibility induced by remarkable intragranular void and irregular shape, calcareous sand presents different mechanical behaviors from common terrestrial sands. Considerable efforts have been made to explore the static and dynamic mechanical properties of calcareous sand. In this paper, a series of monotonous experiments have been performed on calcareous sand utilizing the electrohydraulic servo-controlled test apparatus designed by the Global Digital Systems Ltd (GDS). The effects of confining pressure and relative density on the mechanical properties of dry, drained, and undrained saturated sand were studied, and the underlying micromechanism of deformation and failure was discussed. It can be found that the residual stress of dry calcareous sand is independent of the relative density, while the peak stress and residual stress of drainage saturated sand have a positive correlation with the relative density. The increase of confining pressure makes the strain softening more remarkable and heightens the peak stress and residual stress. The stress-strain curve of calcareous sand can be divided into two portions: prepeak portion and postpeak softening portion. For the dry sand and drainage saturated sand, the softened part can be partitioned into three phases, i.e., accelerated phase, steady phase, and degradation phase, while the undrained saturated sand tends to hyperbolic softening. A mathematical model composed of a hyperbolic function and an inverted S-shaped function was formulated to describe the multiphase characteristic, in which the setting of parameter p expands its applicability. The experimental result validated the model, showing that the model can better describe the monotonic stress-strain relationship of calcareous sand. Besides, the physical meanings of model parameters were discussed. [ABSTRACT FROM AUTHOR]

Background: Lymph node involvement is recognized as a prognostic factor for patients with gallbladder cancer. However, the N stage varied from different editions of the American Joint Committee on Cancer (AJCC) TNM Classification. Our objective was to investigate the impact of lymph node involvement on overall survival in elderly patients with non-metastatic gallbladder adenocarcinoma., Methods: Patients older than 65 years with non-metastatic gallbladder adenocarcinoma were identified from the SEER data. We used Cox proportional hazard regression analysis to select the independent risk factor. A nomogram was built to identify the 1-, 3-, and 5-years' prognostic impact. Univariate and multivariate models were used to examine the correlation of overall survival (OS) with the number of metastatic nodes., Results: A total of 1,654 patients (706 with and 948 without nodal involvement) were included. Cox proportional hazard regression analyses found that age, gender, tumor size, lymph node involvement, and surgical options were risk factors for the prognosis and were integrated into the nomogram. After adjustment, OS was compromised for patients who receive surgery with nodal involvement [hazard ratio (HR), 2.238; P  < 0.01]. Furthermore, after adjustment the presence of more than two metastatic lymph nodes was associated with decreased OS (HR, 3.305; P  < 0.01)., Conclusions: Our results suggest that lymph node involvement is associated with compromised survival in elderly patients. A nomogram was developed to predict the prognosis of gallbladder cancer. A change point of more than two metastatic lymph nodes seems to carry prognostic significance, calling for closer monitoring of elderly patients with gallbladder cancer with involvement of increased number of lymph nodes., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2024 Huang, Qiu, Bai and He.)

Cholangiocarcinoma, classified as intrahepatic, perihilar, and extrahepatic, is considered a deadly malignancy of the hepatobiliary system. Most cases of cholangiocarcinoma are asymptomatic. Therefore, early detection of cholangiocarcinoma is significant but still challenging. The routine screening of a tumor lacks specificity and accuracy. With the application of AI, high-risk patients can be easily found by analyzing their clinical characteristics, serum biomarkers, and medical images. Moreover, AI can be used to predict the prognosis including recurrence risk and metastasis. Although they have some limitations, AI algorithms will still significantly improve many aspects of cholangiocarcinoma in the medical field with the development of computing power and technology., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Huang, Bai, Qiu and He.)