The present research used a combination of experimental and numerical methods to investigate energy dissipation blocks of different heights placed downstream of a sluice gate in an open channel flow. ...Numerical model simulations were performed using a 3D computational fluid dynamics (CFD) technique, using the Reynolds-averaged Navier-Stokes (RANS) equations with the volume of fluid (VOF) and k-epsilon turbulence models. The accuracy of the numerical model and the grid sensitivity was assessed according to a recommended procedure in the literature. Different hydraulic and geometry conditions were investigated to understand the energy dissipation behaviour of the blocks. The hydrodynamic effects of different block spacings, heights and configurations were analysed by means of CFD simulations. The results show that the variable size blocks have a high energy dissipation efficiency in sluice gate flows, particularly at high Froude numbers. The energy dissipation efficiency of the blocks downstream of a sluice gate can reach up to 55% for high discharges (Q = 35 L/s). Interestingly, the energy dissipation performance of small gate openings exceeds that of large gate openings, reaching a peak efficiency of 40% for the same discharge. In addition, the block spacing has a minimal effect on the energy dissipation, while smaller block spacing results in a smoother water surface profile.
The novel coronavirus pneumonia (COVID-19) is a highly infectious acute respiratory disease caused by Severe Acute Respiratory Syndrome-Related Coronavirus (SARS-CoV-2) (Prec Clin Med 2020;3:9-13, ...Lancet 2020;395:497-506, N. Engl J Med 2020a;382:1199-207, Nature 2020;579:270-3). SARS-CoV-2 surveillance is essential to controlling widespread transmission. However, there are several challenges associated with the diagnostic of the COVID-19 during the current outbreak (Liu and Li (2019), Nature 2020;579:265-9, N. Engl J Med 2020;382:727-33). Firstly, the high number of cases overwhelms diagnostic test capacity and proposes the need for a rapid solution for sample processing (Science 2018;360:444-8). Secondly, SARS-CoV-2 is closely related to other important coronavirus species and subspecies, so detection assays can give false-positive results if they are not efficiently specific to SARS-CoV-2. Thirdly, patients with suspected SARS-CoV-2 infection sometimes have a different respiratory viral infection or co-infections with SARS-CoV-2 and other respiratory viruses (MedRxiv 2020a;1-18). Confirmation of the COVID-19 is performed mainly by virus isolation followed by RT-PCR and sequencing (N. Engl J Med 2020;382:727-33, MedRxiv 2020a, Turkish J Biol 2020;44:192-202). The emergence and outbreak of the novel coronavirus highlighted the urgent need for new therapeutic technologies that are fast, precise, stable, easy to manufacture, and target-specific for surveillance and treatment. Molecular biology tools that include gene-editing approaches such as CRISPR-Cas12/13-based SHERLOCK, DETECTR, CARVER and PAC-MAN, antisense oligonucleotides, antisense peptide nucleic acids, ribozymes, aptamers, and RNAi silencing approaches produced with cutting-edge scientific advances compared to conventional diagnostic or treatment methods could be vital in COVID-19 and other future outbreaks. Thus, in this review, we will discuss potent the molecular biology approaches that can revolutionize diagnostic of viral infections and therapies to fight COVID-19 in a highly specific, stable, and efficient way.
Siphon-shaft spillways are constituted by covering above a shaft spillway with a hood that creates siphonic pressure. This study focused on the aeration the flow through the aerator holes placed on ...the hood to prevent cavitational damage in high-head siphon-shaft spillways. Three-dimensional computational fluid dynamics (CFD) technique using finite-volume method to solve Reynolds-averaged Navier–Stokes (RANS) equations for the incompressible viscous and turbulent fluids motion was performed to analyze the full-scaled two-phase numerical models. The volume of fluid (VOF) scheme was used to simulate two-phase (water–air) flow, by defining the volume fraction for each of the fluids throughout the solution domain. The accuracy of the numerical model was tested using a procedure recommended by American Society of Mechanical Engineers (ASME) for CFD applications. The numerical results showed that the aeration is highly effective in reducing siphon sub-pressures and cavitation. The optimal relative aeration diameter of 0.45 provided sufficient air entrainment to protect from cavitation and did not decrease the discharge performance too much.
Objective: Continuous inflammation at the level of the vascular endothelium plays an important role in the formation of hypertension. Diurnal blood pressure (BP) variation also is a risk factor for ...hypertensive target organ damage. This study planned to evaluate these inflammation processes in normotensive and hypertensive patients.
Methods: This study is observational cross-sectional cohort in-design. 151 patients with a prediagnosis of hypertension included. The patients were divided into three groups (group 1: dipper normotensive, group 2: non-dipper normotensive, group 3: dipper-hypertensive) based on the results of ambulatory blood pressure monitoring. The groups were compared in terms of systemic inflammation index (SII; platelet count×neutrophil count/lymphocyte count), neutrophil to lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and other inflammation processes.
Results: There was a significant difference between the three groups in terms of mean platelet volume (MPV) and red blood cell distribution width (RDW) levels (p=0.001 and p<0.001, respectively). A statistically significant difference was found between the groups in terms of NLR, PLR, systemic inflammation index, lymphocyte-monocyte ratio (LMR). In subgroup analysis, NLR and systemic inflammation index were similar in group 2 and group 3, but higher than in group 1 in both groups. LMR was similar in group 2 and group 3 but lower than in group 1. In subgroup analysis PLR levels were similar in group 2 and group 3 but higher than group 1 in both groups.
Conclusion: This study showed that normotensive non-dipper patients had inflammation as much as dipper hypertensive patients according to measurement of MPV, RDW systemic inflammation index, PLR, NLR levels.
Hepatitis C virus (HCV) infects over 170 million people worldwide and is the leading cause of chronic liver diseases, including cirrhosis, liver failure, and liver cancer. Available antiviral ...therapies cause severe side effects and are effective only for a subset of patients, though treatment outcomes have recently been improved by the combination therapy now including boceprevir and telaprevir, which inhibit the viral NS3/4A protease. Despite extensive efforts to develop more potent next-generation protease inhibitors, however, the long-term efficacy of this drug class is challenged by the rapid emergence of resistance. Single-site mutations at protease residues R155, A156 and D168 confer resistance to nearly all inhibitors in clinical development. Thus, developing the next-generation of drugs that retain activity against a broader spectrum of resistant viral variants requires a comprehensive understanding of the molecular basis of drug resistance. In this study, 16 high-resolution crystal structures of four representative protease inhibitors--telaprevir, danoprevir, vaniprevir and MK-5172--in complex with the wild-type protease and three major drug-resistant variants R155K, A156T and D168A, reveal unique molecular underpinnings of resistance to each drug. The drugs exhibit differential susceptibilities to these protease variants in both enzymatic and antiviral assays. Telaprevir, danoprevir and vaniprevir interact directly with sites that confer resistance upon mutation, while MK-5172 interacts in a unique conformation with the catalytic triad. This novel mode of MK-5172 binding explains its retained potency against two multi-drug-resistant variants, R155K and D168A. These findings define the molecular basis of HCV N3/4A protease inhibitor resistance and provide potential strategies for designing robust therapies against this rapidly evolving virus.
Due to high flow velocity, the spillway surfaces of high-head dams can expose to cavitational damage. The most effective and economical method of protection from this damage is aerated to flow using ...aerators. In this study, a spillway aerator of the roller-compacted concrete dam of 100 m height was analyzed using two-phase computational fluid dynamic model to overcome the cavitation damage on the spillway surface. The numerical analysis with prototype dimensions was performed for various flow conditions (5223, 3500, 1750 and 1000 m
3
/s of flow rate), and obtained results were compared with some experimental observation in the literature. Numerical and experimental results indicated that the cavitation occurs on the surface after a certain downstream point based on cavitation indices. The air entrainment rate and air concentrations supplied by means of the aerator were determined to avoid the cavitational damage. While the experimental results can contain considerable scale effect in terms of air entrainment rate owing to, e.g., viscous effects especially for small scales, the numerical models with prototype dimensions gave much more accurate results. In other words, it can be also mentioned that the actual aeration amount is much greater than that obtained from the model experiments. The results based on numerical analysis showed that the aerator device meet air demand to prevent the cavitation damage.
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