The implicit Colebrook equation is considered as a fundamental equation for estimating the friction factor for turbulent flows in pipes. A large number of simple and accurate explicit approximations cover just a limited area of turbulent regime inside rough or smooth pipes. Here, three explicit approximations of the friction factor were determined. The friction factor data were fitted into polynomials using the response surface design of Minitab software. To reduce the relative error of the first approximation compared with the implicit Colebrook equation, the domain was divided into two regions based on the Reynolds number (Re). To compare the accuracy and complexity of the approximations with existing relations, advanced comparison analysis based on the relative error was performed. The second set of approximations defined in two ranges of Re demonstrated high accuracy and a satisfying complexity index.
Background and aims: Curcumin or diferuloylmethane is derived from ferulic acid. This herbal compound has a particular chemical structure and various biological/medical properties. The functional groups in the curcumin structure and its analogs are involved in the formation of specific biological activities. This natural compound has high bioactivity, as well as the potential to treat diseases such as cancer, Alzheimer’s, diabetes, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Considering the spread of infectious diseases and cancers in recent years, as well as an increase in drug resistance and side effects, providing effective and available treatments is necessary. Methods: This review explained the chemical structure of curcumin and covered its biological properties, including anti-inflammation, antioxidant, anti-cancer, neuroprotective, anti-diabetic, and anti-SARS-CoV-2 activities. Scientific databases were studied to gather the required information. Results: Curcumin affected several molecular pathways, including activating transcription factors, cell growth factors, anti-inflammatory agents, protein kinases, cytokines, and apoptotic pathway factors. Thus, it had beneficial therapeutic effects on health. Conclusion: By targeting a wide range of molecular mechanisms, curcumin has the potential to treat various diseases. Knowledge of curcumin’s pharmacological/biological activities and its action mechanisms can enhance the applications of curcumin as a potentially bioactive and therapeutic compound.
Background and aims: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a newly discovered coronavirus which causes an infectious disease. The severe acute respiratory syndrome (SARS-CoV) and the Middle East respiratory syndrome (MERS) broke out in 2003 and 2012, respectively. These viruses have some structural proteins, including spike (S), membrane (M), envelope (E), and nucleocapsid (N) proteins. These proteins assist the virus in infecting cells through interaction with cell receptors, penetration into the cell, and proliferation. These coronavirus proteins are modified by post-translational modifications (PTMs) which activate various functional and interactional activities of proteins. This study aimed to investigate the PTMs in SARS-CoV/CoV-2, as well as to examine the effect of these PTMs on the pathogenicity of these two viruses. Methods: In this study, PTMs sites were detected by different bioinformatics tools. Evaluation and comparison of PTMs were performed and their roles in structural proteins activities of SARS-CoV/CoV-2 coronaviruses were examined in order to gain a richer understanding of these modifications’ relationships with the protein activities. Results: The PTMs sum and percentages of four structural proteins of SARS-CoV/CoV-2 were evaluated, with a focus on their effects on viral replication and pathogenesis in order to develop a method for treating these diseases. According to our study results, some of the PTMs in SARS-CoV/CoV-2 were different from each other. Conclusion: It was concluded that SARS-CoV-2 had more pathogenicity than SARS-CoV.
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