162 research outputs found

    Remarks on the tensor degree of finite groups

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    The present paper is a note on the tensor degree of finite groups, introduced recently in literature. This numerical invariant generalizes the commutativity degree through the notion of nonabelian tensor square. We show two inequalities, which correlate the tensor and the commutativity degree of finite groups, and, indirectly, structural properties will be discussed.Comment: 5 pages; to appear with revisions in Filoma

    Mechanical and Microstructure Characteristics of Concrete-Mixtures Designed for Durability of RC-Structures in Corrosive Environment

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    As exposures to chloride-salts are known as prime factors causing initiation and continuity of corrosion-process of steel reinforcement bars in reinforced concrete (RC) structures, it has always been a major concern for designers considering the requirements of structural-durability for targeted-service life of RC-structures in aggressively corrosive environments typically prevalent in coastal regions. Research works previously reported by the researchers have modeled corrosion-process in terms of corrosion-current density, and it was realized that concrete-mixtures design quality and characteristics, degree of exposures to corrosive-agents such as chloride salts, and protective-concrete cover-thickness are now known beyond doubt to be determinant factors as regards RC-structures durability. This research paper is focused on presenting highlights of an extensive experimental investigation carried out on a large number of concrete specimens that were designed, and placed in chloride-salt solution simulating exposure to corrosion-conditions. Results presented in this paper include close-looks at mechanical and micro-structure characteristics with regard to the influence of key design-parameters and exposure-conditions used for test-specimens with various combinations of cementitious materials constituents and proportioning using three replicate-combinations of water-cementitious ratios, fine to total aggregate ratio, and concrete-cover thickness, and with different concentrations of chloride-solution. Statistical analysis of results obtained from a three-year test-program is outlined in terms of one unifying corrosion-process progress indicator, namely, corrosion-current density Icorr, determined by both electrochemicalmethod and gravimetric weight-loss method. The paper presents a general overview of the test program and a summary of sample results on mechanical, strength, and microstructural characteristics obtained from test specimens

    A regularity criterion in multiplier spaces to Navier-Stokes equations via the gradient of one velocity component

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    In this paper, we study regularity of weak solutions to the incompressible Navier-Stokes equations in R3×(0,T)\mathbb{R}^{3}\times (0,T). The main goal is to establish the regularity criterion via the gradient of one velocity component in multiplier spaces.Comment: 9 pages. arXiv admin note: text overlap with arXiv:2005.1401

    Smoking cessation during COVID-19: the top to-do list

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    As evidence continues to emerge, our understanding of the relationship between smoking and COVID-19 prognosis is steadily growing. An early outlook from World Health Organisation (WHO) indicates that smokers are more vulnerable to severe COVID-19 disease and are also more likely to be infected, as frequent motions from hand to mouth and sharing of tobacco products such as waterpipes increased the possibility of being infected. In this commentary, we discuss some of the latest evidence on smoking and COVID-19 and emphasise the need to promote the personal and public advantages of smoking cessation during the COVID-19 pandemic

    Effect of Gallium-68 isotope injection on hemoglobin derivatives concentrations after instant injection and its recovery in male rabbits (Oryctolagus cuniculus)

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    Oxidizing effects of ionizing radiation are well established and almost understood. However, exposure to low doses of widely used isotopes may result in minor and hidden oxidative stress in some forms of hemoglobin. This formation alteration regarding the legends of hemoglobin's stereochemical function may play a role in hemoglobin dysfunction. There are limited studies related to the effect of gallium isotope injections.  The study intends to find the effect of gallium-68 isotope injection on male rabbits. It was conducted on thirty-two male rabbits (Orycytolagus cuniculus) divided into Group I: control and Group II: animals exposed to gallium-68 isotope at a similar dose commonly used in diagnostic protocols for humans. Blood samples were collected twice: the first was after two hours of injection with isotopes and the second was after twelve hours of injection. A linear, four-mathematical-equations matrix based on the Lamber-Beer law was used to measure the concentration of different hemoglobin derivatives. Results revealed a significant elevation (P<0.05) of methemoglobin, the oxidized form of hemoglobin, two hours after injection (Total hemoglobin = 4.463 ± 0.83), but this effect was completely reversed after twelve hours. This concluded that even low doses of isotopes result in oxidation of hemoglobin that recovers shortly. Furthermore, the outcome of the study supports the healthcare centres to understand the effect of gallium-68 injections on animals.           

    Mechanisms of colorectal cancer cell growth and metastasis inhibition by CARP-1 functional mimetic-4

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    Introduction: Colorectal cancer (CRC) constitutes one of the most aggressive malignancies worldwide and in Malaysia. Due to high recurrence rate and toxic side effects associated with radiation and chemotherapies, new agents are urgently needed. CARP-1 is a peri-nuclear phospho-protein which plays a dynamic role in regulating cell growth and apoptosis. CARP-1 functional mimetics (CFMs) are a class of compounds that stimulate CARP-1. CFM-4, a lead compound, was shown to suppress growth and metastasis of various cancers, other than CRC. We hypothesized that CFM-4 inhibits proliferation and metastasis in CRC. Material and methods: CFM-4 anti-cancer effects of on CRC cells were investigated using MTT assay, Annexin V/Propidium iodide (PI) apoptosis assay, cell cycle analysis, quantitative real-time PCR (qRT-PCR) and Western blotting. Antimetastatic activities were assessed by migration, colony formation and invasion assays. Results: CFM-4 inhibited CRC cell proliferation and was much more potent than the classical anti-CRC 5-fluorouracil. These effects were shown to be mediated at least in part by stimulating apoptosis, as indicated in our Annexin V/PI assay results. Cell cycle analysis showed that CFM-4 induced G2/M phase arrest. Molecularly, qRT-PCR results revealed that CFM-4 promoted intrinsic apoptosis by upregulating expression of caspase-8 and -9, p53, PUMA and Noxa, and stimulated extrinsic apoptosis by enhancing expression of death receptors. CFM-4 upregulated NF-B signaling inhibitor A20-binding inhibitor protein and the PI3K negative regulator PTEN. Western blot analysis results revealed that CFM-4 enhanced expression of CARP-1, caspase-8 and executioner caspase-3. Metastatic properties of the CRC cells were reduced by CFM-4 through blocking their capabilities to form colonies, migrate and invade through the matrix-coated membranes. Conclusion: The potent antitumor and anti-metastatic properties of CFM-4 against CRC are due to collective pro-apoptotic, anti-proliferative and anti-metastatic activities. Together our data warrants further investigations of CFM-4 as potential anti-tumor agent for CRC malignancy and metastasis

    A Predictive Model for Steady State Ozone Concentration at an Urban-Coastal Site

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    Ground level ozone (O3) plays an important role in controlling the oxidation budget in the boundary layer and thus affects the environment and causes severe health disorders. Ozone gas, being one of the well-known greenhouse gases, although present in small quantities, contributes to global warming. In this study, we present a predictive model for the steady-state ozone concentrations during daytime (13:00–17:00) and nighttime (01:00–05:00) at an urban coastal site. The model is based on a modified approach of the null cycle of O3 and NOx and was evaluated against a one-year data-base of O3 and nitrogen oxides (NO and NO2) measured at an urban coastal site in Jeddah, on the west coast of Saudi Arabia. The model for daytime concentrations was found to be linearly dependent on the concentration ratio of NO2 to NO whereas that for the nighttime period was suggested to be inversely proportional to NO2 concentrations. Knowing that reactions involved in tropospheric O3 formation are very complex, this proposed model provides reasonable predictions for the daytime and nighttime concentrations. Since the current description of the model is solely based on the null cycle of O3 and NOx, other precursors could be considered in future development of this model. This study will serve as basis for future studies that might introduce informing strategies to control ground level O3 concentrations, as well as its precursors’ emissions
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