93 research outputs found

    Effect of Changing Properties of Wythes in Precast Structural Sandwich Panels

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    This study investigates the effects of changing in the properties of face and core wythes in structural sandwich panels (with dimensions of 500 500 mm and 120 mm total height). Concrete face wythes of three grades (80, 70, 37) MPa, thicknesses of (25, 35, and 45) mm, and three types of core materials (high density foam, polyethylene foam, and palm bark) were used in the production of panels. Steel shear connectors were installed in the panels with angle of 45º. Three-point bending load test was carried out on all panels and results were compared with both of the theoretical extremes capacities of non- composite and fully-composite states and ANSYS software results. The degree of composite action (%) and the (strength/weight) ratio were the main parameters that judged the specimens. It was found that upgrading concrete increased overall strength of slabs especially in high strength concrete (80 MPa), however the use of lightweight concrete (70 MPa) caused high (strength/weight) ratio due to very lightweight. Results revealed that decreasing thickness of concrete face wythes had a positive effect on strength/weight ratio (although the ultimate loads decreased) that enhanced the performance of panels as lightweight structural panels. The optimum face wythe thickness is that of 2.5 cm and has high (strength/weight) ratio. It was noticed that adding polyethylene foam as a core material results in positive effect and high (strength/weight) ratio. Results revealed that high strength concrete (80 MPa) and light-weight concrete (37 MPa) are very successful in the production face wythes of precast light-weight sandwich panels that can obtain high (strength/weight) ratio and high percent of composite action

    Origin of Amphibole-Biotite-Fluorite-Rich Enclaves from Gabal El-Ineigi Fluorite-Bearing Granite, Central Eastern Desert of Egypt: Insights into Fluoride-Calcium and Silicate Liquid Immiscibility

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    Gabal El-Ineigi fluorite-bearing rare-metal granite with A-type affinity, located in the Central Eastern Desert of Egypt, is distinguished by its abundance of large fluorite-quartz veins and mafic enclaves. Plagioclase (labradorite to oligoclase), Mg-rich biotite, and Mg-rich hornblende are the main components of mafic enclaves, with significant amounts of fluorite as essential phases, and titanite and Fe-Ti oxides (Nb-free rutile and ilmenite-rutile solid solution) as the main accessories. These enclaves are monzodioritic in composition, Si-poor, and highly enriched in Ca, Fe, Mg, and F compared to the host alkali feldspar F-poor Si-rich granites. Given the conflicting evidence for a restitic, xenolithic, magma mixing/mingling, cumulate, or bimodal origin for these enclaves, we propose that the mafic enclaves and felsic host granites are two conjugate liquids, with contrasting compositions, of a single parental melt. This is inferred by the normalized REE patterns that are similar. As a result, liquid immiscibility is proposed as a probable explanation for this mafic–felsic rock association. These enclaves can be interpreted as transient melt phases between pure silicate and calcium-fluoride melts that are preserved from the early stages of separation before evolving into a pure fluoride (Ca-F) melt during magma evolution. Due to element partitioning related to melt unmixing, the enclaves are preferentially enriched in Ca, F, Li, Y, and REE and depleted in HFSE (such as Zr, U, Th, Ta, Nb, Hf, and Ga) in comparison to the host granites. Furthermore, mafic enclaves exhibit W-type tetrad effects, while host granites exhibit M-type tetrad effects, implying that the REE partitioning, caused by liquid immiscibility, is complementary

    Review of the utilization of HEEPF – competitive projects for educational enhancement in the Egyptian medical sector

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    In Egypt, the medical sector has been facing the same problems that challenged the system of higher education in the past decades, mainly an increasing student enrollment, limited resources, and old governance and bylaws. These constraints and the escalating paucity of resources have had a major negative influence on quality of education. Consequently, thoughts of educational reform came forward in the form of competitive projects, which have attracted several institutes from the health sector to improve their educational performance. The aim of this paper is to review the share of the medical sector in the higher education enhancement project fund (HEEPF), its outcomes, sustainability, and to provide recommendations for keeping the momentum of reform pursuit in the future. The methodology included obtaining statistics pertaining to the medical sector in Egypt as regards colleges, students, and staff. We also reviewed the self-studies of the medical sector colleges, HEEPF projects reports, performance appraisal reports, and World Bank reports on HEEPF achievements in order to retrieve the required data. Results showed that medical sector had a large share of the HEEPF (28.5% of projects) as compared to its size (8% of student population). The projects covered 10 areas; the frequency distribution of which ranged between 4.4% (creation of new programs) to 97.8% (human resource development). In conclusion, educational enhancement in the medical sector in Egypt could be apparently achieved through the HEEPF competitive projects. A study of the long-term impact of these projects on the quality of education is recommende

    Investigation of the Ameliorating Effect of Copper Albumin Complex on Lysyl oxidase in monosodium iodoacetate -Induced Knee Osteoarthritis in Rats

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    Knee osteoarthritis (KOA) is a common type of joint degeneration which causes progressive damage of the joint structure and has less therapeutic options. It has been found that oral consumption of Copper Albumin Complex as anti-inflammatory drug has a positive effect on the treatment of joint deterioration. The present study aimed to investigate the effect of oral administration of Copper Albumin Complex (cu-albumin complex) on Lysyl oxidase (LOX) which acts as a protective factor in KOA. Fifty adult albino rats were divided into 3 groups: negative control (10 normal rats); positive control (20 rats with KOA which left without induction treatment); and treated group (20 rats with KOA which treated with administration of copper albumin complex). Treated and untreated arthritic groups were subdivided equally into mild and severe groups (10 rats for each) according to the severity of clinical signs. KOA was induced by intra-articular injection of monosodium iodoacetate (MIA). At the experimental end, the joints were examined histopathologically and immunohistochemically after cervical dislocation of rats. It was observed that the treatment with CU- was effective in reducing disease severity and in improvement of Lysyl oxidase KOA. It was concluded that Copper albumin complex has a positive effect in the improvement of LOX of Knee joint cartilages of rats affected by osteoarthritis (OA)

    In ovo protective effects of chicoric and rosmarinic acids against Thiacloprid-induced cytotoxicity, oxidative stress, and growth retardation on newly hatched chicks

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    Thiacloprid (TH) is a neonicotinoid insecticide employed in agriculture to protect fruits and vegetables against different insects. It showed different deleterious effects on the general health of non-target organisms including birds and animals, however, its developmental toxicity has yet to be fully elucidated. Chicoric (CA) and rosmarinic (RA) acids are polyphenolic compounds with a wide range of beneficial biological activities. In this study, the possible protective effects of CA and RA were investigated in chick embryos exposed in ovo to TH (1mg/egg) with or without CA (100 mg/egg) or RA (100 mg/egg) co-exposure. TH reduced the hatchling body weight, body weight/egg weight, and relative weight of bursa of Fabricius in the one-day-old hatchlings. Examination of the 7-day-old chicks revealed a decline in feed intake, daily weight gain, feed conversion ratio (FCR), and plasma levels of T3, T4, and growth hormone. Serum ALT, AST activities, and total cholesterol levels showed significant elevations. Hepatic MDA was increased with a reduction in SOD activity and GSH level and downregulation of the liver SOD and GST gene expression pattern. Serum IgG and IgM levels were reduced, and various histopathological alterations were noticed in the liver. Co-administration of CA or RA with TH mitigated the toxic effects on hatchlings. When both CA and RA are combined, they present a synergistic protective effect. CA and RA can be used as protective agents against TH toxicity as they improve growth performance and have hepatoprotective and immunostimulant effects in newly hatched chicks

    Perspective Chapter: The Toxic Silver (Hg)

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    In the late 1950s, residents of a Japanese fishing village known as “Minamata” began falling ill and dying at an alarming rate. The Japanese authorities stated that methyl-mercury-rich seafood and shellfish caused the sickness. Burning fossil fuels represent ≈52.7% of Hg emissions. The majorities of mercury’s compounds are volatile and thus travel hundreds of miles with wind before being deposited on the earth’s surface. High acidity and dissolved organic carbon increase Hg-mobility in soil to enter the food chain. Additionally, Hg is taken up by areal plant parts via gas exchange. Mercury has no identified role in plants while exhibiting high affinity to form complexes with soft ligands such as sulfur and this consequently inactivates amino acids and sulfur-containing antioxidants. Long-term human exposure to Hg leads to neurotoxicity in children and adults, immunological, cardiac, and motor reproductive and genetic disorders. Accordingly, remediating contaminated soils has become an obligation. Mercury, like other potentially toxic elements, is not biodegradable, and therefore, its remediation should encompass either removal of Hg from soils or even its immobilization. This chapter discusses Hg’s chemical behavior, sources, health dangers, and soil remediation methods to lower Hg levels

    Thymoquinone Induces Telomere Shortening, DNA Damage and Apoptosis in Human Glioblastoma Cells

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    Background: A major concern of cancer chemotherapy is the side effects caused by the non-specific targeting of both normal and cancerous cells by therapeutic drugs. Much emphasis has been placed on discovering new compounds that target tumour cells more efficiently and selectively with minimal toxic effects on normal cells. Methodology/Principal Findings: The cytotoxic effect of thymoquinone, a component derived from the plant Nigella sativa, was tested on human glioblastoma and normal cells. Our findings demonstrated that glioblastoma cells were more sensitive to thymoquinone-induced antiproliferative effects. Thymoquinone induced DNA damage, cell cycle arrest and apoptosis in the glioblastoma cells. It was also observed that thymoquinone facilitated telomere attrition by inhibiting the activity of telomerase. In addition to these, we investigated the role of DNA-PKcs on thymoquinone mediated changes in telomere length. Telomeres in glioblastoma cells with DNA-PKcs were more sensitive to thymoquinone mediated effects as compared to those cells deficient in DNA-PKcs. Conclusions/Significance: Our results indicate that thymoquinone induces DNA damage, telomere attrition by inhibiting telomerase and cell death in glioblastoma cells. Telomere shortening was found to be dependent on the status of DNA-PKcs. Collectively, these data suggest that thymoquinone could be useful as a potential chemotherapeutic agent in th
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