Search

Reservoir impoundment and water level fluctuations often trigger landslides and their secondary disasters, such as potential impulse waves, posing a serious threat to the safety of people along the reservoir and dam areas, causing economic losses and even catastrophic consequences. This study delves into a comprehensive field investigation and monitoring of the engineering geological conditions and deformation mechanisms of the Mogu rock landslide. The impoundment is identified as the primary factor inducing slope deformation, with the cumulative displacement of the sliding body showing no signs of convergence, indicating potential instability. By coupling the elasto-visco-plasticity model and the RNG turbulence model in FLOW-3D, an actual impulse wave disaster near the Lianghekou reservoir dam area is replicated to validate the reliability of the numerical method. Building upon this, a three-dimensional model is established to calculate potential impulse waves generated by the Mogu rock landslide, and the risk to the dam is evaluated. Under different water level conditions, the simulated run-ups of impulse waves do not surpass the dam elevation, demonstrating a satisfactory safety margin. Given the inherent danger of landslide-induced wave disasters, continuous attention is warranted, and preventive measures and suggestions are proposed to address these concerns. Additionally, the study explores the contributions of water level fluctuations to the primary tsunami amplitude, the maximum run-up on the opposite bank and the dam, and the attenuation rate of the tsunami amplitude along the river channel. The results provide significant reference values for the early warning and prevention of comparable reservoir landslides and potential landslide-induced waves worldwide. [ABSTRACT FROM AUTHOR]

Landslide-generated impulse waves (LGIWs) often cause enormous damage. This study proposes a two-way coupled discrete element method (DEM) and smoothed particle hydrodynamics (SPH) method to study the whole hazard chain of LGIWs in mountain reservoirs. In this method, a two-way coupling code is developed to connect the DEM program Particle Flow Code 3D (PFC3D) and the SPH code DualSPHysics for simulating landslide sliding and fluid motion. A series of discretization operations are conducted to transform the DEM balls into discrete balls composed of SPH particles, and the dynamic boundary condition method is used to calculate the interaction forces between fluid and solid phases. This work is validated through a comparative analysis with published physical model experiments. Using the proposed method, the LGIWs induced by the RS deposit in the RM reservoir is simulated. The processes of landslide motion, impulse waves generation, propagation, and running up on the dam are studied. The results show that the proposed method possesses the capability to simulate and predict the hazards of LGIWs. This article represents the first implementation of PFC3D within a coupled DEM-SPH framework to study LGIWs, and provides a valuable way for assessing the associated risks. [ABSTRACT FROM AUTHOR]

With the acceleration of innovative drugs launched in the market, clinical trials have become increasingly complex and costly. Integration of patients' perspective and engagement into the clinical research process is essential to the success of the trials, which leads to the emergence of the concept of patient-centric clinical trials. Compared to the conventional paradigm of clinical trials, patient-centric clinical trials have the potential to increase the feasibility of study protocol, to speed recruitment and execution, and to promote the success of trials. It calls for the institutions and investigators of clinical trials to be aware of and adapt to patient-centric initiatives. In this article, we highlight technologies and actions that can be used to enhance patients' engagement in the entire process of drug development, covering protocol development, trial conduction, and result publication.

When excavating the rock foundation of a hydropower station, it will be affected by the phenomenon of unloading and relaxation, which may increase the risk of stability of the dam foundation engineering system. The dam foundation of Baihetan Hydropower is a columnar jointed rock mass (CJRM), which presents strong brittleness and anisotropy compared to traditional dam foundation rocks. Therefore, this type of rock mass is prone to disturbance to the dam body, structure, etc. during excavation, so it is necessary to accurately evaluate the impact of dam foundation excavation. Establishing a rock mass creep models serve as an effective tool for evaluating such stability but often suffer from significant parameter uncertainty. Digital twin technology, a virtual model, is capable of real-time learning from actual monitoring data obtained from the physical entity to enhance the performance of the built-in mechanistic model. In this study, the researchers employ the classical Burgers constitutive equation as the theoretical framework and integrate it with an ensemble smoother with multiple data assimilation (ESMDA) method based on Bayesian principles, along with displacement monitoring data from the Baihetan Dam foundation, to construct a digital twin model. Within this framework, the researchers analyze the uncertainty of rheological parameters at various measurement points in the Baihetan Dam foundation. Subsequently, the most suitable rheological parameters are selected and incorporated into the constitutive model to obtain displacement estimates, which are then compared with on-site monitoring data. The results demonstrate that the proposed method effectively performs probabilistic parameter estimation and model prediction for rheological mechanics. This research integrates data-driven methods with mechanical principles, offering a reliable approach for assessing the uncertainty of unloading rheological parameters and displacement prediction in dam foundations, thereby providing essential support for the evaluation of excavation projects in the CJRM of the Baihetan Dam foundation. [ABSTRACT FROM AUTHOR]

Large deformations of soft rocks often occur during the excavation and support of the Chuxiong section tunnel in the Yunnan Central Diversion Project. The physical characteristics and creep mechanical properties of the red-bed soft rock were analyzed by combining engineering experience, laboratory tests, and scanning electron microscopy. Furthermore, the creep parameters of the red-bed soft rock were obtained. The issues related to large deformations of deeply buried tunnels with soft and weak rock masses were investigated. Based on construction engineering practice and numerical simulations, characteristics of extrusion damage of deeply buried tunnels with soft and weak rock masses were analyzed. Countermeasures were implemented to solve the problems of large deformations, which can be used as references for the construction of similar soft rock tunnels in the future. [ABSTRACT FROM AUTHOR]

Interleukin-6 (IL-6), a pleiotropic cytokine, plays a crucial role in acute stress induced by bacterial infection and is strongly associated with reactive oxygen species (ROS) production. However, the role of IL-6 in the liver of fish after Aeromonas hydrophila infection remains unclear. Therefore, this study constructed a zebrafish (Danio rerio) il-6 knockout line by CRISPR/Cas9 to investigate the function of IL-6 in the liver post bacterial infection. After infection with A. hydrophila, pathological observation showed that il-6−/− zebrafish exhibited milder liver damage than wild-type (WT) zebrafish. Moreover, liver transcriptome sequencing revealed that 2432 genes were significantly up-regulated and 1706 genes were significantly down-regulated in il-6−/− fish compared with WT fish after A. hydrophila infection. Further, gene ontology (GO) analysis showed that differentially expressed genes (DEGs) were significantly enriched in redox-related terms, including oxidoreductase activity, copper ion transport, etc. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that DEGs were significantly enriched in pathways such as the PPAR signaling pathway, suggesting that il-6 mutation has a significant effect on redox processes in the liver after A. hydrophila infection. Additionally, il-6−/− zebrafish exhibited lower malondialdehyde (MDA) levels and higher superoxide dismutase (SOD) activities in the liver compared with WT zebrafish following A. hydrophila infection, indicating that IL-6 deficiency mitigates oxidative stress induced by A. hydrophila infection in the liver. These findings provide a basis for further studies on the role of IL-6 in regulating oxidative stress in response to bacterial infections. [ABSTRACT FROM AUTHOR]

In constructing hydraulic tunnels, construction disturbances and complex geological conditions can induce variations in the surrounding rock parameters. To navigate the complex non-linear interplay between rock material parameters and tunnel displacement during construction, this study proposes a hybrid learning model. It employs particle swarm optimization (PSO) to refine the hyperparameters of the eXtreme Gradient Boosting (XGBoost) technique. Sensitivity analysis and inversion of rock parameters is performed by using orthogonal design and the Sobol method to analyze the sensitivity of environmental and rock material factors. The findings indicate that the tunnel depth, elastic modulus, and Poisson ratio are particularly sensitive parameters. Mechanical parameters of the rock mass, identified through sensitivity analysis, are the focal point of this research and are integrated into a three-dimensional computational model. The resulting tunnel displacement calculations serve as datasets for the inversion of the actual engineering project's surrounding rock mechanical parameters. These inverted parameters were fed into the FLAC3D software (version 7.0), yielding results that align closely with field measurements, which affirms the PSO-XGBoost model's validity and precision. The insights garnered from this research offer a substantial reference for determining rock mass parameters in tunnel engineering amidst complex conditions. [ABSTRACT FROM AUTHOR]