Promotion of proliferation and metastasis of hepatocellular carcinoma by LncRNA00673 based on the targeted-regulation of notch signaling pathway

we read with great interest the paper by Dr. Chen et al1, recently published in European Review for Medical and Pharmacological Sciences and titled ‘‘Promotion of proliferation and metastasis of hepatocellular carcinoma by LncRNA00673 based on the targeted-regulation of notch signaling pathway’’. Authors concluded that lncRNA00673 is highly expressed and may be a potential target for the treatment of Hepatocellular Carcinoma (HCC). Moreover, according to authors, it can promote the proliferation and metastasis of HCC by the regulation of Notch signaling pathway. We congratulate the authors for their interesting work

Computational Fluid Dynamics Modelling of Two-Phase Bubble Columns: A Comprehensive Review

Bubble columns are used in many different industrial applications, and their design and characterisation have always been very complex. In recent years, the use of Computational Fluid Dynamics (CFD) has become very popular in the field of multiphase flows, with the final goal of developing a predictive tool that can track the complex dynamic phenomena occurring in these types of reactors. For this reason, we present a detailed literature review on the numerical simulation of two-phase bubble columns. First, after a brief introduction to bubble column technology and flow regimes, we discuss the state-of-the-art modelling approaches, presenting the models describing the momentum exchange between the phases (i.e., drag, lift, turbulent dispersion, wall lubrication, and virtual mass forces), Bubble-Induced Turbulence (BIT), and bubble coalescence and breakup, along with an overview of the Population Balance Model (PBM). Second, we present different numerical studies from the literature highlighting different model settings, performance levels, and limitations. In addition, we provide the errors between numerical predictions and experimental results concerning global (gas holdup) and local (void fraction and liquid velocity) flow properties. Finally, we outline the major issues to be solved in future studies

Computational fluid dynamics simulation of the heterogeneous regime in a large-scale bubble column

Bubble columns are used in many industrial applications, but the complex fluid dynamics phenomena has limited their design and optimization processes. Computational Fluid Dynamics (CFD) is a promising tool to investigate the complex multi-scale flow physics characterising multiphase reactors. In this work, a CFD Eulerian-Eulerian modelling approach is developed to describe the hydrodynamics of a large-scale bubble column operated over a wide range of superficial gas velocities (0.0188 – 0.20 m/s). Available experimental results were used for the model validation. A drag law for oblate bubbles was considered and coupled with a drag modification function to include the effects of bubble–bubble interactions. The numerical approach was tested considering a mono-dispersed approximation and including coalescence and breakup by using a Population Balance Model (PBM). The role played by the lift force was investigated and, for the reactor configuration considered, it turned out to be essential in the description of the local flow properties

Numerical investigation of film thickness and wave statistics in gas-liquid downwards annular flows

Two-phase gas-liquid annular flows are observed in a broad range of industrial processes, such as production and pipeline systems for oil and gas distribution, steam generators, boiling water reactors, and emergency core cooling facilities to protect nuclear reactors. Although the global flow characteristics of annular gas-liquid flows have been studied experimentally for more than 50 years, their numerical modelling is still immature. We present a computational fluid dynamics model based on the volume of fluid method for simulating annular gas-liquid flows, focusing on the regular wave flow regime. We performed transient simulations on a 3-D domain using a commercial code (ANSYS Fluent 2021 R1). The mesh sensitivity analysis indicates that a very fine mesh must be used near the pipe wall to capture the liquid-gas interface correctly (Fig. 1). The code is validated through available experimental data [1] regarding topological flow properties. In particular, we considered mean film thickness, film roughness, base film thickness, and wave film thickness. We studied two operating conditions. The first is characterized by liquid and gas Reynolds numbers of 1 250 and 25 000, respectively. The second has the same liquid Reynolds number as the first, but the gas Reynolds number is increased to 30 000. A post-processing procedure is implemented to obtain the time traces of film thickness at 12 circumferential positions to capture the asymmetries in the flow. The numerical values of the quantities analyzed are in good agreement with the experimental findings, with a maximum error of 21.02% concerning the wave film thickness. The errors regarding the mean film thickness and film roughness are less than 10% for both the case studies. Considering the film thickness of time traces at different circumferential positions, we calculated the cross-correlation coefficients between them. The high values of the cross-correlation coefficients indicate that waves are coherent over the circumference of the pipe, following the experimental findings. Finally, to better understand wave activities, we generated the power spectral density functions for the two cases studied. They are characterized by a quasi-linear power decay, similar to that of the Kolmogorov spectrum for homogeneous and isotropic turbulence, which becomes slightly steeper for the case characterized by a higher gas Reynolds number, in accordance with the experimental data

Two Phase Bubble Columns: the Determinants of the Flow Regime Transitions

The fluid dynamics in large-diameter bubble columns can be described by an analytical relation between two global flow parameters, the drift flux and the gas holdup. This relation, named bubble column operating curve, builds on five flow regime transitions. In order to determine the variables influencing the flow regime transitions, a statistical approach was derived by coupling: (1) the ordinary least squares method (OLS) to determine the relationship between the variables, (2) the variance inflation factor (VIF) to check for multicollinearity issues, and (3) the least absolute shrinkage and selection operator (LASSO), to select suitable variables. It was found that the geometrical characteristics of the sparger strongly influence the flow regime transitions, and uniform aeration is essential for all the regimes to exist. Increasing the superficial liquid velocity in the counter-current mode destabilises the mono-dispersed and poly-dispersed homogeneous flow regimes. As for the aspect ratio, an increase in the column aspect ratio slightly destabilises the existing flow regimes. The statistical method identifies viscosity as the only significative variable concerning the liquid phase properties

Computational fluid dynamics modelling of the regular wave flow regime in air-water downwards annular flows

Although the global flow characteristics of annular gas-liquid flows have been studied experimentally for more than 50 years, the spatiotemporally-resolved details of these flows have remained relatively unexplored until recently, with data provided via advanced experimental methods based, e.g., on optical techniques. Similarly, the numerical modelling of annular flows is still an immature process. The present work aims to provide a computational fluid dynamics (CFD) model based on the volume of fluid (VOF) method for simulating annular gas-liquid flows, setting the stage for a deeper investigation of these flows at global and local scales. The work focuses on the most common downwards annular flow (DAF) flow pattern: the regular wave regime. 3-D and 2-D axisymmetric transient simulations have been performed using a commercial code (ANSYS Fluent 2021 R1). The code is validated through available experimental data regarding topological flow properties, mainly film thickness and wave statistics. The validation results suggest that 3-D simulations are needed to provide predictions that agree with the experimental data, highlighting strong 3-D features in the flow

Maximum-likelihood retrieval of volcanic ash concentration and particle size from ground-based scanning lidar

An inversion methodology, named maximum-likelihood (ML) volcanic ash light detection and ranging (Lidar) retrieval (VALR-ML), has been developed and applied to estimate volcanic ash particle size and ash mass concentration within volcanic plumes. Both estimations are based on the ML approach, trained by a polarimetric backscattering forward model coupled with a Monte Carlo ash microphysical model. The VALR-ML approach is applied to Lidar backscattering and depolarization profiles, measured at visible wavelength during two eruptions of Mt. Etna, Catania, Italy, in 2010 and 2011. The results are compared with those of ash products derived from other parametric retrieval algorithms. A detailed comparison among these different retrieval techniques highlights the potential of VALR-ML to determine, on the basis of a physically consistent approach, the ash cloud area that must be interdicted to flight operations. Moreover, the results confirm the usefulness of operating scanning Lidars near active volcanic vents

Cognitive Impairment and Age-Related Vision Disorders: Their Possible Relationship and the Evaluation of the Use of Aspirin and Statins in a 65 Years-and-Over Sardinian Population

Neurological disorders (Alzheimer’s disease, vascular and mixed dementia) and visual loss (cataract, age-related macular degeneration, glaucoma, and diabetic retinopathy) are among the most common conditions that afflict people of at least 65 years of age. An increasing body of evidence is emerging, which demonstrates that memory and vision impairment are closely, significantly, and positively linked and that statins and aspirin may lessen the risk of developing age-related visual and neurological problems. However, clinical studies have produced contradictory results. Thus, the intent of the present study was to reliably establish whether a relationship exist between various types of dementia and age-related vision disorders, and to establish whether statins and aspirin may or may not have beneficial effects on these two types of disorders. We found that participants with dementia and/or vision problems were more likely to be depressed and displayed worse functional ability in basic and instrumental activities of daily living than controls. Mini mental state examination scores were significantly lower in patients with vision disorders compared to subjects without vision disorders. A closer association with macular degeneration was found in subjects with Alzheimer’s disease than in subjects without dementia or with vascular dementia, mixed dementia, or other types of age-related vision disorders. When we considered the associations between different types of dementia and vision disorders and the use of statins and aspirin, we found a significant positive association between Alzheimer’s disease and statins on their own or in combination with aspirin, indicating that these two drugs do not appear to reduce the risk of Alzheimer’s disease or improve its clinical evolution and may, on the contrary, favor its development. No significant association in statin use alone, aspirin use alone, or the combination of these was found in subjects without vision disorders but with dementia, and, similarly, none in subjects with vision disorders but without dementia. Overall, these results confirm the general impression so far; namely, that macular degeneration may contribute to cognitive disorders (Alzheimer’s disease in particular). In addition, they also suggest that, while statin and aspirin use may undoubtedly have some protective effects, they do not appear to be magic pills against the development of cognitive impairment or vision disorders in the elderly