28 research outputs found
Correlation of Osteocalcin with Vitamin D Level in Postmenopausal Women Concerning CYP24A1 and VDR Gene Polymorphisms
No full textBackground: Vitamin D is an essential agent in regulating body enzymes due to the wide distribution of vitamin D receptors throughout the body, the site where vitamin D acts. Vitamin D deficiency could be related to many factors. Polymorphism in receptor(s) and enzyme(s) responsible for vitamin D metabolism, like CYP24A1, could be liable for vitamin D deficiency.
Objective: This study aims to determine the impact of polymorphism in Vitamin D Receptor TaqI (rs731236) and CYP24A1 (rs2762934 and rs4809957) on vitamin D level and osteocalcin in postmenopausal women.
Subjects and Methods: Forty postmenopausal osteoporotic women (patients’ group) according to WHO osteoporosis diagnostic criteria were enrolled in the study. This group received 50000 IU/week of vitamin D for eight weeks. In addition, 30 postmenopausal non-osteoporotic women were set to be a control group. Genetic and biochemical analyses were applied for both groups.
Results: Serum levels of osteocalcin in the patients’ group were 9±6.19 and 4±6.6 in groups with vitamin D levels below 20nmole/L and above 20nmole/L, respectively, with a non-significant difference between them (p=0.49). Related to allele frequency, the A/G genotype of rs731236 of the vitamin D receptor, G/G genotype of rs2762934, and A/A genotype of rs4809957 of CYP24A1 showed non-significant differences among the study patients’ group.
Conclusions: Our data indicates that rs731236 with the A/G genotype, rs2762934 with the G/G genotype, and rs4809957 with the A/A genotype were more prevalent than the other genotypes and could be responsible for being osteoporotic through their effect on vitamin D level and resistance to vitamin D supplementations.
Flexural Behavior of Hybrid Fiber Reinforced SCC Beams with Longitudinal and Bubble Voids
No full textTo investigate the flexural behavior of self-consolidating hybrid fiber-reinforced concrete beams containing voids experimentally, six RC beams were tested, one solid without fiber and the others containing hooked-steel and macro-polypropylene fibers with a volume fraction of 1 and 0.5%, respectively. One of the five fibrous beams was solid; two contain a series of recycled plastic balls of diameters 110 and 120 mm, and another two contain a single longitudinal circular void created by PVC pipes of diameters 90 and 110 mm. The flexural behavior of the beams was assessed depending on the load-deflection curve, load-strain curve, ductility, toughness, stiffness, and crack patterns. The experimental outcomes showed that all the tested specimens (solid and voided) failed in a flexural mode. Hybrid fiber inclusion in the solid beam improved the load capacity at different loading levels, enhanced the stiffness by 38.3%, and increased the absorbed energy by 29.55%. The presence of voids in fibrous beams decreased the loads at cracking, yielding, and ultimate stages and enhanced the ductility. The ductility index, depending on deflection and energy methods, showed higher values for voided beams. The toughness of voided beams at the ultimate stage was enhanced by 1.1% to 28%. The voided beams exhibited lower values of stiffness, and their values decreased when the diameter of the voids increased. The outcomes also indicated that the incorporation of hybrid fiber significantly minimized the strain in steel reinforcing bars at the post-cracking stage, and the presence of voids minimized the reduction effect of steel strain according to void size and shape. Doi: 10.28991/CEJ-2025-011-04-08 Full Text: PD
Flexural Moment Capacity Evaluation of Reinforced RPC Two-way Slabs
No full textThis paper presents calculations to determine the flexural moment capacity of Reactive Powder Concrete (RPC) two-way slabs depending on three models from previous studies (Model 1, Model 2, and Model 3). The outcomes of these calculations were compared with experimental results to tempt the accuracy and the applicability of the adopted theoretical models. The experimental program included testing three simply supported RPC two-way slabs of 1000 mm length, 1000 mm width, and 70 mm thickness. The tested specimens were of identical properties except their steel fibers volume ratios (0.5 %, 1 %, and 1.5 %). It was found out that the first model (Model 1) is the most suitable among the three models, where its outcomes were very close to the corresponding experimental data, while Model 2 was underestimated the failure load, and Model 3 was overestimated it by large differences, where the maximum difference between the theoretical and experimental failure load according to the mentioned three models was 3.4%, 48.2%, and 87.2% respectively.
 
Behavior of Reinforced Reactive Powder Concrete Two-Way Slabs under Static and Repeated Load
No full textThis paper studies the behavior of reinforced Reactive Powder Concrete (RPC) two-way slabs under static and repeated load. The experimental program included testing six simply supported RPC two-way slabs of 1000 mm length, 1000 mm width, and 70 mm thickness. All the tested specimens were identical in their material properties, and reinforcement details except their steel fibers content. They were cast in three pairs, each one had a different steel fibers ratio (0.5 %, 1 %, and 1.5 %) respectively. In each pair, one specimen was tested under static load and the other under five cycles of repeated load (loading-unloading). Static test results revealed that increasing steel fibres volume fraction from 0.5 % to 1 % and from 1% to 1.5%, led to an increase in the: first crack load by (32.2 % and 52.3 %), ultimate load by (36.1 % and 17.0 %), ultimate deflection by (33.6 % and 3.4 %), absorbed energy by (128 % and 20.2 %), and the ultimate strain by (1.1 % and 6.73 %). It also increased the stiffness and the ductility of the specimens especially at the final stages of loading. Additionally, it delayed the propagation of the cracks, controlled their growth, kept the integrity of the specimens at post cracking stage, and avoided their ruin at the failure stage through its "bridging” effect. For the repeated load test, applying five cycles of repeated load to the steel fiber reinforced RPC two-way slab specimens led to a decreasing in the ultimate load capacity, ultimate deflection, ultimate strain, and absorbed energy in a comparison with the corresponding static test specimens, and that because of the loading-unloading process which causes a fluctuation of stresses and more damages in concrete. Increasing the steel fibers volume fractions decreased the dissipated energy of the specimens that subjected to a repeated load, where the difference percent of dissipated energy between the first and second cycles of (R0.5 %, R1 %, and R1.5 %) specimens were (68.0 %, 46.2%, and 32.4%) respectively
SERUM INTERLEUKIN 13 (IL-13) LEVELS IN IRAQI CHILDREN WITH NEPHROTIC SYNDROME.
No full textThe aim of this study is to compare the levels of IL-13 in children with nephrotic syndrome and healthy control children. Fifty children with NS were divided into four groups: 14 steroid sensitive infrequent relapse (SSIFR), 12 steroid sensitive frequent relapse (SSFR), 9 steroid resistance (SR) and 15 newly diagnosis (ND) compared to twenty-five unrelated healthy children. The serum IL-13 levels for NS patients and healthy control children were measured by R&D quantitative ELISA kit. The results of mean IL-13 level in healthy children serum (205.18 ? 2.61 pg/ml) was significantly lower than children with NS (335.50 ? 40.68 pg/ml). we showed serum IL-13 was increased significantly (P= 0.0271) in children with NS in compared with healthy control children, this raised in IL-13 levels could have a role in nephrotic syndrome pathogenesis
Contribution of Fill-Concrete Compressive Strength on the Structural Performance of CFSST Columns: An Analytical Study
No full textHigh-rise structures are a significant indication in contemporary urban improvement, mainly in areas characterized by accelerated urban growth and dense population. This type of building should be designed to withstand severe load conditions. Therefore, using composite structural elements in such structures is required for stronger and durable elements. This paper introduces a finite element analysis model for Concrete Filled Stainless Steel Tubular Columns (CFSST) of (100x100) mm cross-section and (1250) mm length to inspect the impact of concrete compressive strength on the response of (CFSST). The generated model was first evaluated through a comprehensive comparison with experimental research. Then, after the model was used to study the considered parameter, namely, concrete compressive strength. A wide range of concrete compressive strengths was included (45, 50, 55, 60, 65, 70, and 75) MPa. FE results indicated that the CFSST columns' ultimate strength is directly proportional to the fill-concrete compressive strength. The optimum gained load capacity was (416 kN) when the concrete strength was 75MPa. The modification of increasing fill-concrete compressive strength extended to include the stiffness, toughness, and the yield load to be (89, 38.9, and 64 %), respectively, as the strength increased to 75MPa. The response improvement didn’t include the ductility index. A reduction in the ductility index was observed as the filled-concrete compressive strength increased, reaching 15.4% when the compressive strength reached 65 MPa. This reduction remains constant, even though the compressive strength increases (from 70 to 75 MPa)
Pre- and Post-Cracking Resistance of Steel Fiber Reinforced Concrete Flexural Members with GFRP Bars
No full textThis research investigates the pre- and post-cracking resistance of steel fiber-reinforced concrete specimens with Glass Fiber Reinforced Polymer (GFRP) bars subjected to flexural loading. The purpose is to modify the ductility and cracking resistance of GFRP-reinforced beams, which are prone to early cracking and excessive deflections instigated by the low modulus of elasticity of GFRP. Six self-compacting concrete specimens (1500×240×200 mm), incorporating steel fibers of two lengths (25 mm and 40 mm) with varying distribution depths, were tested to assess their structural performance. The results indicate significant enhancements in cracking resistance, stiffness, energy absorption, ductility, and flexural strength. Tested beams reinforced with 40 mm-long steel fibers exhibited a 23.9%–24.2% development in the ultimate moment capacity associated with the steel-reinforced specimens, whereas those with 25 mm fibers showed smaller increases (2.7%–3.1%). The cracking resistance improved by up to 33.3% in beams with 40 mm-long fibers and by 16.67%–20% in those with 25 mm-long fibers, associated with a non-fibrous GFRP specimen. Additionally, the inclusion of 40 mm hooked-end steel fibers significantly enhanced ultimate deflection, with peak deflections increasing by 30.2%–44.8% compared to steel-reinforced beams. Fibrous GFRP-reinforced beams exhibited up to 154% higher energy absorption under ultimate load than a non-fibrous GFRP beam. All fibrous GFRP-reinforced beams achieved deformation-based ductility indices between 4.2 and 6.9, exceeding the minimum threshold of 4 for adequate deformability. These findings confirm that incorporating 40 mm steel fibers significantly improves the structural behavior of GFRP-reinforced concrete specimens, offering valuable insights for optimizing their design
Unraveling the influence of organic cations on tuning electronic structures and spin-splitting in two-dimensional layered organic-inorganic tin-iodine perovskites
No full textThe solar cell and light-emitting device research community is currently focusing on investigating two-dimensional (2D) hybrid perovskite materials owing to their remarkable stability and intriguing optoelectronic characteristics, which hold significant promise for various applications. In general, the introduction of chirality in hybrid perovskites arises from symmetry breaking within their inorganic frameworks. Nevertheless, despite this understanding, the specific factors driving the observed increase in splitting remain obscure due to a lack of comprehensive investigations. Our research delves into the electronic properties of 2D layered hybrid perovskites, considering their behavior with and without spin-orbit coupling. We specifically focus on effect of Rashba splitting and the impact of electronic structure variation across a range of chiral perovskites by introducing chiral organic cations with differing degrees of π-conjugation, resulting in significant changes in spin-splitting magnitude. Systematic first principles investigations confirm that the distortion of the cage and d-spacing of chiral perovskites are crucial design parameters for achieving strong spin-splitting in 2D layered perovskites. Furthermore, our investigation reveals that these systems exhibit remarkable absorption capabilities in the visible light spectrum, as demonstrated by their computed optoelectronic characteristics. The chiral perovskites described in this study, which exhibit substantial spin-splitting, present a distinctive prototype with potential implications for spintronics and photovoltaics.This project was funded by the Deanship of Scientific Research (DSR) at King Abdulaziz University, Jeddah, under grant no. KEP-PhD:83-130-1443. The authors, therefore, acknowledge with thanks DSR for technical and financial support. The authors are also grateful to the HPCC (Aziz Supercomputer) for the resources. A. J. is grateful to the KAUST Supercomputing Laboratory (Shaheen II) for the provided resources
On the Impact of Lacing Reinforcement Arrangement on Reinforced Concrete Deep Beams Performance
No full textThe optimum design is characterized by structural concrete components that can sustain loads well beyond the yielding stage. This is often accomplished by a fulfilled ductility index, which is greatly influenced by the arrangement of the shear reinforcement. The current study investigates the impact of the shear reinforcement arrangement on the structural response of the deep beams using a variety of parameters, including the type of shear reinforcement, the number of lacing bars, and the lacing arrangement pattern. It was found that lacing reinforcement, as opposed to vertical stirrups, enhanced the overall structural response of deep beams, as evidenced by test results showing increases in ultimate loads, yielding, and cracking of 30.6, 20.8, and 100%, respectively. There was also a 53.6% increase in absorbed energy at the ultimate load. The shear reinforcement arrangement had a greater impact and a significant effect on the structural response than the number of lacing bars. For lacing reinforcement with a phase difference equivalent to the half-lacing cycle (i.e., phase lag lacing), the percentage of improvement under different loading stages was 6.7-27.1% and 20.8-113.3%, respectively. The structural responses are significantly impacted by the lacing arrangement; members with two and three lacing bars, respectively, exhibited improvements in ultimate load of 30.6% and 47%. Beyond the yielding stage, the phase lag lacing specimens deviated from those without phase lag lacing and normal shear stirrups because of the lacing contribution. Phase lag specimens showed more strain than specimens without phase lag lacing, meaning that the lacing reinforcement contributed more to the beam strength. It was found that the first shear cracking load of all the laced reinforced specimens was higher than that of the conventional shear stirrup specimens. Phase lag lacing produced the greatest improvement, with two bars achieving 92.44% and three bars achieving 217.07%. For the aforementioned number of bars, lacing shear reinforcement without phase lag was less successful, with 36.91% and 46.53%, respectively. Doi: 10.28991/CEJ-2025-011-02-019 Full Text: PD
