THE APPLICATION OF FRICTION STIR PROCESSING TO THE FABRICATION OF MAGNESIUM-BASED FOAMS

In the present paper, friction stir processing (FSP) is used to fabricate magnesium-based nanocomposite foams. The effects of the number of FSP passes, TiH2 to Al2O3 weight ratio, and foaming temperature; on the pore distribution and porosity are described. The results indicate that a minimum TiH2 to Al2O3 weight ratio is necessary to provide the best pore distribution and porosity. Closed-cell porous magnesium with a porosity of about 17.5% was successfully fabricated using 4-pass FSP at 800 rpm, by adding 5 mass% TiH2 and 3.5 mass% Al2O3; at a holding temperature of 858 K, and a holding time of 45 min.111Ysciescopu

Association between levels of vitamin D and inflammatory markers in healthy women

Fawaz Azizieh,1 Khulood O Alyahya,2 Raj Raghupathy3 1Department of Mathematics and Natural Sciences, Gulf University for Science and Technology, Kuwait City, Kuwait; 2Science Department, College of Basic Education, Public Authority for Applied Education and Training, Kuwait City, Kuwait; 3Department of Microbiology, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait Background: No one can deny that the biological importance of vitamin D is much beyond its classical role in bone metabolism. Several recent publications have highlighted its potential role in the functioning of the immune system. The overall objective of this study was to look into possible correlations between levels of vitamin D and inflammatory markers in sera of healthy adult women. These markers included proinflammatory cytokines (interleukin [IL]-1β, IL-6, IL-8, IL-17, interferon [IFN]-γ, and tumor necrosis factor [TNF]-α), anti-inflammatory cytokines (IL-4, IL-10, and IL-13), as well as C-reactive protein (CRP) as a general indicator of inflammation. Methods: Venous blood samples were collected from 118 healthy adult women and serum levels of vitamin D, CRP, proinflammatory cytokines (IL-1β, IL-6, IL-8, IL-17, IFN-γ, and TNF-α), and anti-inflammatory cytokines (IL-4, IL-10, and IL-13) were measured. Results: There were no significant direct correlations between serum levels of vitamin D and any of the inflammatory markers measured. However, subjects with deficient levels of vitamin D and high CRP produced significantly higher levels of the proinflammatory cytokines (TNF-α and IL-8) as compared to subjects with low CRP levels with nondeficient and deficient levels of vitamin D. Further, the anti-inflammatory/proinflammatory ratios suggest a role of vitamin D in maintaining an anti-inflammatory environment at low levels of CRP, an association that is weaker at high CRP levels in subjects with subclinical inflammatory situations. Conclusion: These data point to a possible role of vitamin D as a contributing factor in balancing cytokines toward an anti-inflammatory role in inflammatory situations. Keywords: vitamin D, cytokines, adult women, CRP, Kuwai

Circulatory pattern of cytokines, adipokines and bone markers in postmenopausal women with low BMD

Fawaz Y Azizieh,1 Diaa Shehab,2 Khaled Al Jarallah,2 Olusegun Mojiminiyi,3 Renu Gupta,4 Raj Raghupathy51Department of Mathematics and Natural Sciences, International Centre for Applied Mathematics and Computational Bioengineering, Gulf University for Science and Technology, Kuwait City, Kuwait; 2Department of Medicine, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait; 3Department of Pathology, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait; 4Department of Radiology, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait; 5Department of Microbiology, Faculty of Medicine, Kuwait University, Kuwait City, KuwaitObjective: In addition to some well-characterized bone turnover markers (BTMs), cytokines and adipokines have also been suggested to be linked to osteoporosis seen in menopause. However, there is much controversy on the possible association between these markers and bone mineral density (BMD). This study was aimed at measuring circulatory levels of selected cytokines, adipokines and BTMs in postmenopausal women with normal and low BMD.Methods: The study population included 71 post-menopausal women, of whom 25 had normal BMD, 31 had osteopenia and 13 had osteoporosis. Circulatory levels of selected pro-resorptive (TNF-α, IL-1β, IL-6, IL-8, IL-12, IL-17), anti-resorptive (IFN-γ, IL-4, IL-10, IL-13, TGF-β) and five adipokine markers (adiponectin, adipsin, lipocalin-2/NGAL, PAI-1 and resistin) were measured using the Multiplex system and read on the Magpix ELISA platform. Further, two bone turnover markers (PINP, CTX) as well as estradiol levels were assayed from the same samples.Results: While circulatory levels of cytokines were comparable between groups, women with low BMD had statistically significantly higher median circulatory levels of adipokines as compared to those with normal BMD. Further, while levels of CTX were not different between the two groups; PINP, PINP/CTX ratio and estradiol levels were significantly lower in women with low BMD. Levels of adiponectin, PINP, PINP/CTX ratio and estradiol correlated significantly with BMD of the hip and spine.Conclusion: The associations between various markers and BMD are complex and multivariate. Our data provide insights into the possible use of circulatory levels of cytokines, adipokines and bone turnover markers on the pathogenesis of postmenopausal osteoporosis because of the well-documented effects of these molecules on bone tissue and their relevance to osteoporosis.Keywords: cytokines, adipokines, BTM, osteoporosis, menopaus

Effect of friction stir processing on the microstructure of pure magnesium castings

In this paper, the effects of the pin profile and its rotational speed on material flow, microstructure, hardness and grain orientation of the friction-stirred pure Mg castings were investigated. For this purpose, three different tool pin profiles (non-threaded cylindrical, threaded cylindrical and conical) were used with various tool rotational speeds. The material flow, refining and grain growth of the material during the friction stir processing was monitored and then related to the Zener-Hollomon parameter. The grain orientation distribution was also investigated using X-ray diffraction.1112sciescopu

The Application of Friction Stir Processing to the Fabrication of Magnesium-Based Foams

In the present paper, friction stir processing (FSP) is used to fabricate magnesium-based nanocomposite foams. The effects of the number of FSP passes, TiH2 to Al2O3 weight ratio, and foaming temperature; on the pore distribution and porosity are described. The results indicate that a minimum TiH2 to Al2O3 weight ratio is necessary to provide the best pore distribution and porosity. Closed-cell porous magnesium with a porosity of about 17.5% was successfully fabricated using 4-pass FSP at 800 rpm, by adding 5 mass% TiH2 and 3.5 mass% Al2O3; at a holding temperature of 858 K, and a holding time of 45 min

The Application of Friction Stir Processing to the Fabrication of Magnesium-Based Foams

In the present paper, friction stir processing (FSP) is used to fabricate magnesium-based nanocomposite foams. The effects of the number of FSP passes, TiH2 to Al2O3 weight ratio, and foaming temperature; on the pore distribution and porosity are described. The results indicate that a minimum TiH2 to Al2O3 weight ratio is necessary to provide the best pore distribution and porosity. Closed-cell porous magnesium with a porosity of about 17.5% was successfully fabricated using 4-pass FSP at 800 rpm, by adding 5 mass% TiH2 and 3.5 mass% Al2O3; at a holding temperature of 858 K, and a holding time of 45 min