362 research outputs found

    Gravity theory in SAP-geometry

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    The aim of the present paper is to construct a field theory in the context of absolute parallelism (Teleparallel) geometry under the assumption that the canonical connection is semi-symmetric. The field equations are formulated using a suitable Lagrangian first proposed by Mikhail and Wanas. The mathematical and physical consequences arising from the obtained field equations are investigated.Comment: 14 pages, References added and a reference updated, minor correction

    Hydromagnetic Non-Newtonian Flow Near an Oscillating flat Plate under the Action of a Body Force

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    Homocysteine and hematological indices in hemodialysis patients

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    Objectives: To explore the relationship between homocysteine and various hematological indices in hemodialysis patients. Patients and Methods: This case-control study comprised 60 hemodialysis patients and 60 healthy controls matched for gender and age. Hemodialysis duration was 3.2±2.9 year at frequency of 2.6±0.6/week. Hypertension and diabetes were the most common self-reported disorders among the hemodialysis patients. Results: Serum homocysteine was significantly higher in hemodialysis patients than in controls (50.8±9.7 vs. 13.1±3.7 μmol/l, P= 0.000). White blood cell (WBC) and platelet (PLT) counts were significantly higher in hemodialysis patients than in controls [(7.18±2.37 x109/L and 266.3±111.9 x109/L vs 5.95±1.37 x109/L and 222.0±54.1 x109/L) with P= 0.017 and P= 0.045, respectively]. In contrast, red blood cell (RBC), hemoglobin, and hematocrit were significantly lower in hemodialysis patients (3.1±0.5 x1012/L, 8.9±1.5 gm/dl and 26.3±4.6%) than in controls (4.0±0.4 x1012/L, 12.8±1.6 gm/dl and 45.0±4.6%) with P= 0.000. Prothrombin time (PT) and international normalized ratio (INR) were significantly higher in hemodialysis patients compared to controls (16±3 sec and 1±0 vs. 14±0 sec and 1.0±0.1, P= 0.000), whereas activated partial thromboplastin time (APTT) was significantly decreased in hemodialysis patients (25±5 vs 33±2 sec, P= 0.000). Homocysteine correlated directly with WBC count (r= 0.338, P= 0.008) and PLT count (r= 0.369, P= 0.000) whereas inverse correlations were found between homocysteine and RBC count (r=-0.648, P= 0.000), hemoglobin (r=-0.733, P= 0.000) and hematocrit (r=-0.836

    THE EFFECTS OF TEMPERATURE DEPENDENT VISCOSITY AND VISCOUS DISSIPATION ON MHD CONVECTION FLOW FROM AN ISOTHERMAL HORIZONTAL CIRCULAR CYLINDER IN THE PRESENCE OF STRESS WORK AND HEAT GENERATION

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    Temperature dependent viscosity and Viscous Dissipation effects are considered on hydromagnetic natural convection flow from horizontal circular cylinder immersed in an electrically conducting fluid with viscosity proportional to a linear function of temperature in the presence of stress work and heat generation. The partial differential governing equations are transformed to dimensionless forms. The numerical computations are carried out for several values of physical parameters involved in the transformed equations. The resulting nonlinear system of partial differential equations is solved numerically by Keller box method which is an implicit finite difference technique with Newton's linearization method. The features of the flow and heat transfer characteristics for different values of the governing parameters are analyzed and discussed. To support the accuracy of the numerical results, a comparison is made with known results from the open literature for some particular cases of the present study and the results are found to be in good agreement

    Validity of using Single Extruder in Wood Plastic Composite from Rice Straw and High Impact Polystyrene Wastes

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    This work mainly aims to study the validity of using the single extruder in achieving adhesion and compatibility between rice straw fibers and plastic wastes as an attempt for manufacturing wood plastic composite (WPC). A single extruder was used for mixing recycled high impact polystyrene (RHIPS) and Egyptian natural rice straw (RS) after being fibrated mechanically to produce an eco-friendly synthetic wood that can be named as rice straw plastic composite (RSPC). The components have passed through many operations such as drying, extrusion, shredding, etc.). To produce the final product, the flat press technique was used with a hydraulic press. Samples with 60 % mechanically fibrated rice straw (MFRS) ratio were produced. The density test was operated on the samples according to ASTM-D-792 to reveal the density of the composite. The water absorption was determined according to ASTM-D-570. Using the single extruder for blending the two components didn’t achieve high levels of compatibility. However, comparing the results with natural soft, hard wood and medium density fiberboard (MDF) synthetic wood. The prepared RSPC samples exhibited less water absorption and higher density than that of natural and MDF woods

    The relationship between serum osteopontin level and parameters of Chronic Kidney Disease – mineral bone disease in patients on regular hemodialysis

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    Background: Chronic Kidney Disease (CKD) is becoming a major health concern worldwide. For many patients, CKD is associated with substantial morbidity and mortality. Osteopontin (OPN) is an extracellular matrix protein first identified in bone tissue and has pleiotropic functions due to its common expression in the main organs and apparatuses. It is a phosphorylated glycophosphoprotein composed of 314 amino acids, involved in biomineralization and remodeling.Objective: This research aimed to assess the serum level of osteopontin in patients with end-stage renal disease (ESRD) on regular haemodialysis and to correlate osteopontin level in patients with ESRD on hemodialysis with other biomarkers CKD-MBD.Patients & Methods: This Study was conducted on 160 participants that were divided into two groups. Control group included 80 healthy subjects of both sexes, and patients group that included 80 ESRD patients on regular hemodialysis of both sexes. All studied groups were subjected to osteopontin level by enzyme-linked immunosorbent assay (ELISA).Results: Serum osteopontin levels were higher in ESRD patients on regular dialysis than in healthy individuals, where it might have a higher predictive value for CKD development. Also, they were positively correlated with serum phosphorus, serum alkaline phosphatase and serum parathyroid hormone, which are parameters of chronic kidney disease-mineral and bone disorder.Conclusion: Osteopontin may be considered an early marker of chronic kidney disease

    Linear Connections and Curvature Tensors in the Geometry of Parallelizable Manifolds

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    In this paper we discuss curvature tensors in the context of Absolute Parallelism geometry. Different curvature tensors are expressed in a compact form in terms of the torsion tensor of the canonical connection. Using the Bianchi identities some other identities are derived from the expressions obtained. These identities, in turn, are used to reveal some of the properties satisfied by an intriguing fourth order tensor which we refer to as Wanas tensor. A further condition on the canonical connection is imposed, assuming it is semi-symmetric. The formulae thus obtained, together with other formulae (Ricci tensors and scalar curvatures of the different connections admitted by the space) are calculated under this additional assumption. Considering a specific form of the semi-symmetric connection causes all nonvanishing curvature tensors to coincide, up to a constant, with the Wanas tensor. Physical aspects of some of the geometric objects considered are mentioned.Comment: 16 pages LaTeX file, Changed title, Changed content, Added references, Physical features stresse

    Scaffold hopping of α-rubromycin enables direct access to FDA-approved cromoglicic acid as a SARS-CoV-2 M<sup>Pro</sup> inhibitor

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    The COVID-19 pandemic is still active around the globe despite the newly introduced vaccines. Hence, finding effective medications or repurposing available ones could offer great help during this serious situation. During our anti-COVID-19 investigation of microbial natural products (MNPs), we came across α-rubromycin, an antibiotic derived from Streptomyces collinus ATCC19743, which was able to suppress the catalytic activity (IC50 = 5.4 µM and Ki = 3.22 µM) of one of the viral key enzymes (i.e., MPro). However, it showed high cytotoxicity toward normal human fibroblasts (CC50 = 16.7 µM). To reduce the cytotoxicity of this microbial metabolite, we utilized a number of in silico tools (ensemble docking, molecular dynamics simulation, binding free energy calculation) to propose a novel scaffold having the main pharmacophoric features to inhibit MPro with better drug-like properties and reduced/minimal toxicity. Nevertheless, reaching this novel scaffold synthetically is a time-consuming process, particularly at this critical time. Instead, this scaffold was used as a template to explore similar molecules among the FDA-approved medications that share its main pharmacophoric features with the aid of pharmacophore-based virtual screening software. As a result, cromoglicic acid (aka cromolyn) was found to be the best hit, which, upon in vitro MPro testing, was 4.5 times more potent (IC50 = 1.1 µM and Ki = 0.68 µM) than α-rubromycin, with minimal cytotoxicity toward normal human fibroblasts (CC50 &gt; 100 µM). This report highlights the potential of MNPs in providing unprecedented scaffolds with a wide range of therapeutic efficacy. It also revealed the importance of cheminformatics tools in speeding up the drug discovery process, which is extremely important in such a critical situation

    Telleparallel Lagrange Geometry and a Unified Field Theory: Linearization of the Field Equations

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    The present paper is a natural continuation of our previous paper: "Teleparallel Lagrange geometry and a unified field theory, Class. Quantum Grav., 27 (2010), 045005 (29pp)" \cite{WNA}. In this paper, we apply a linearization scheme on the field equations obtained in \cite{WNA}. Three important results under the linearization assumption are accomplished. First, the vertical fundamental geometric objects of the EAP-space loose their dependence on the positional argument xx. Secondly, our linearized theory in the Cartan-type case coincides with the GFT in the first order of approximation. Finally, an approximate solution of the vertical field equations is obtained.Comment: 18 pages, LaTeX fil
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