Behavior and Analysis of Cracked Self-Compacted Reinforced Concrete Beams

The objectives of this paper are to compare between the fracture parameters of self compacting concrete (SCC) and normal vibrating concrete (NVC). The fracture behavior of both the plain and reinforced concrete beam specimens under three point bending (3PB) was investigated. It was found that the values of fracture toughness in reinforced concrete beams increased with increasing the notch – depth ratio, increasing the area of steel bars in cross section and with using dolomite as coarse aggregate in the mix. The self compacting concrete beams exhibit good fracture toughness than those of normal concrete at all the used variables. A model of Hillerborg was used to predict the fracture toughness of notched concrete beams

Flexural Behavior of Lightweight Composite Ferrocement Plates

In recent years, producing lightweight structures is considered as one of the most important application of concrete. It has extensive applications in the architect and insulation work. The main objective of this study is to investigate the behavior and the performance of lightweight ferrocement (LWF) composite plates with lightweight materials as filler materials in flexural. Fifteen lightweight ferrocement (LWF) composite plates were investigated by conducting flexural tests. The main variables are (the thickness of plates, the type of filler materials, the type and number of layers of meshes). The behavior of lightweight ferrocement (LWF) composite plates is investigated by conducting flexural tests on fifteen simply supported rectangular plates under three lines loadings. Fifteen plates represented in twelve lightweight ferrocement (LWF) plates and three conventional reinforced concrete (RC) plates. The ferrocement plates were divided into three groups according to the thickness of plates 6cm, 8cm and 10cm. The structural performances of the LWF and RC plates are investigated in terms of crack load, load-deflection curves, stiffness, energy absorption capacity, ductility index, ultimate flexural load-to-weight ratio, load-strain curves, crack patterns, and the failure modes. The test results revealed remarkable enhancement in the flexural behavior and potential application of lightweight ferrocement (LWF) composite plates to produce lightweight structural elements as compared to that of the reinforced concrete (RC) plates, which lead towards the industrialization of building system and meets with innovation and expansible application of concrete construction technology results in better efficiency of developing of lightweight composite ferrocement plates

Serum OX40 ligand: a potential marker of atopic dermatitis disease severity in children

Background: OX40 ligand (OX40L) and OX40 are members of the tumor necrosis factor (TNF) and TNF receptor (TNFR) super families respectively. Recent studies have indicated the critical involvement of OX40/OX40L interaction in the pathogenesis of atopic dermatitis. To our knowledge, no data could be cited in literature concerning OX40L levels in serum or in other biological fluids of atopic dermatitis children. Objective: This study was done to explore the expression of OX40L in the serum of atopic dermatitis children with respect to disease activity and severity. Methods: This follow-up, case-control longitudinal study was conducted on 64 children as a stratified non-random sample; 34 with atopic dermatitis and 30 healthy children. Serum concentrations of OX40L were measured by sandwich enzyme immunoassay. The severity of atopic dermatitis was assessed according to the Leicester Sign Score (LSS), Simple Scoring System (SSS), Scoring Atopic Dermatitis (SCORAD) index, and Objective SCORAD. Results: Serum OX40L levels (pg/ml) in atopic dermatitis patients were significantly elevated as compared to controls (176.6 ± 45.9) whether during flare (1007 ± 241.5) or quiescence (699 ± 198.5). There were significant positive correlations between serum OX40L levels and each of the LSS, SSS and SCORAD indices of atopic dermatitis disease severity, while it was insignificant regarding the objective SCORAD. However, when atopic dermatitis children were classified according to the objective SCORAD index of severity into mild, moderate and severe, it was found that the mean serum level in the severe group was significantly higher than the corresponding values of the mild or the moderate group. OX40L levels did not correlate with serum total IgE or absolute eosinophils count. Serum total LDH levels correlated positively with each of the serum OX40L levels and the LSS and SCORAD indices of severity. Conclusions: Serum OX40L level is an objective reliable marker of atopic dermatitis severity in children. It may be useful for follow up and may help to improve research and management of this disease. Blockade of interactions between OX40 on Th2 cells and OX40L on activated dendritic cells using an OX40L-specific monoclonal antibody could represent a novel strategy for the treatment of atopic dermatitis.Keywords: Atopic dermatitis, LSS, OX40, OX40L, SCORAD, SSS, TNFEgypt J Pediatr Allergy Immunol 2009;7(1):15-2

Roselle (Hibiscus sabdariffa L.) seeds as unconventional nutritional source

The composition of roselle seed from oil, protein, ash, fiber, fatty acids and amino acids was determined and compared in three cultivars in order to use it as an unconventional nutritional source. Aswan cv. occupies the highest significant rank in protein (31.51), oil (23.70) and fiber (4.87%) contents. Aswan and Sewa cvs. had the highest significant unsaturated fatty acid composition, especially oleic and linoleic acids, with oleic acid having values of 36.22 and 33.34% and linoleic acid, 14.95 and 15.10% values. Protein of Aswan cv. had the highest significant values of seven essential amino acids and four non-essential amino acids, especially lysine and phenylalanine.Key words: Amino acids, fatty acids, nutrition, oil, protein, roselle, unconventional crops

Comparative analysis of the efficacy of astigmatic correction after wavefront-guided and wavefront-optimized LASIK in low and moderate myopic eyes

AIM: To evaluate and compare the efficacy of the astigmatic correction achieved with laser in situ keratomileusis (LASIK) in eyes with myopic astigmatism using wavefront-guided (WFG) and wavefront-optimized (WFO) ablation profiles. METHODS: Prospective study included 221 eyes undergoing LASIK: 99 and 122 eyes with low and moderate myopic astigmatism (low and moderate myopia groups). Two subgroups were differentiated in each group according to the ablation profile: WFG subgroup, 109 eyes (45/64, low/moderate myopia groups) treated using the Advanced CustomVue platform (Abbott Medical Optics Inc.), and WFO subgroup, 112 eyes (54/58, low/moderate myopia groups) treated using the EX-500 platform (Alcon). Clinical outcomes were evaluated during a 6-month follow-up, including a vector analysis of astigmatic changes. RESULTS: Significantly better postoperative uncorrected visual acuity and efficacy index was found in the WFG subgroups of each group (P≤0.041). Postoperative spherical equivalent and cylinder were significantly higher in WFO subgroups (P≤0.003). In moderate myopia group, a higher percentage of eyes with a postoperative cylinder ≤0.25 D was found in the WFG subgroup (90.6% vs 65.5%, P=0.002). In low and moderate myopia groups, the difference vector was significantly higher in the WFO subgroup compared to WFG (P<0.001). In moderate myopia group, the magnitude (P=0.008) and angle of error (P<0.001) were also significantly higher in the WFO subgroup. Significantly less induction of high order aberrations were found with WFG treatments in both low and moderate myopia groups (P≤0.006). CONCLUSION: A more efficacious correction of myopic astigmatism providing a better visual outcome is achieved with WFG LASIK compared to WFO LASIK.Partially supported by a grant from Abbott Medical Optics

CHOLESTATIC LIVER FIBROSIS IN A RAT MODEL OF BILE DUCT LIGATION: EVALUATING BIOCHEMICAL VERSUS HISTOPATHOLOGICAL CHANGES

Objective: Bile duct ligation (BDL), chronic liver injury model, was extensively used in studying mechanisms of fibrogenesis and antifibrotic agents. Considering the liver regenerative capacity and the diverse results from BDL, the present study aimed to evaluate the biochemical and histopathological changes over 10 weeks following BDL assessing if BDL-induced changes remain in a deterioration state or improve at a certain stage.Methods: Sham operation and BDL were conducted in Male Wistar rats. Serum AST, ALT, total bilirubin and albumin and hepatic hydroxyproline (HYP), reduced glutathione (GSH) and malondialdehyde (MDA) were measured in sham-operated (n=3) and BDL-rats (n=6) at 0, 1, 2, 4, 6, 8 and 10 weeks following operation. Liver tissue was also processed for histopathological analysis (H&amp;E and Sirus red staining).Results: Progressive liver injury (H&amp;E) and collagen deposition (Sirus red and HYP) in BDL-rats were observed starting from the first week post-operation and reached their maximum with early signs of cirrhosis on the 10th week of BDL. Severe and sustained cholestatic injury appeared in 2 weeks (increased ALT, AST, bilirubin along with decreased albumin (P&lt;0.001) compared to sham-operated rats). AST peaked on first week, however, bilirubin, ALT and MDA peaked on the 4th week (P&lt;0.001) then gradually decreased compared to their peaks.Conclusion: The relative improvement in liver function/cholestasis following their peaks in BDL model despite progression of fibrosis and hepatic injury require investigators using this model to consider not only biochemical, but also histopathological findings to guarantee an accurate interpretation of their results.Â

New Technique to Improve the Ductility of Steel Beam to Column Bolted Connections: A Numerical Investigation

From MDPI via Jisc Publications RouterHistory: accepted 2021-10-12, pub-electronic 2021-10-22Publication status: PublishedA novel method to improve the robustness of steel end plate connections is presented in this paper. Existing commonly adopted techniques alter the stiffness of the beam or the end plate to improve the connection’s robustness. In this study, the robustness is enhanced by improving the contribution of the bolts to the rotational capacity of connections; the higher the bolts’ elongation, the higher the rotational capacity that can be achieved. However, the brittleness of the bolt material, combined with its small length, results in negligible elongation. Alternatively, the load path between the end plate and the bolts can be interrupted with a ductile element to achieve the required elongation. This can be achieved by inserting a steel sleeve with a designated length, thickness, and wall curvature between the end plate and the washer. The proposed sleeve should be designed so that its ultimate capacity is less than the force in the bolt at failure; accordingly, the sleeve develops a severe bending deformation before the failure of any connection components. Using a validated finite element model, end plate connections with various parameters are numerically investigated to understand the performance of the sleeve device. The proposed system substantially enhances the rotational capacity of the connections, ranging between 1.37 and 2.46 times that of the standard connection. It is also concluded that the sleeved connections exhibit a consistent elastic response with the standard connections, indicating the proposed system is compatible with codified elastic design approaches without modification. Furthermore, for a specific connection, various ductile responses can be achieved without altering the connection capacity nor configuration

Potentially toxic elements in saltmarsh sediments and common reed (Phragmites australis) of Burullus coastal lagoon at North Nile Delta, Egypt: A survey and risk assessment

Burullus lagoon is the second largest lake in Egypt. However, there has never been a comprehensive survey which studied nineteen potentially toxic elements in sediments and plants and evaluated the associated potential risk. Thus, we aimed to study the total and potentially available content of As, Al, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Sb, Se, Sn, Tl, V, and Zn in the sediments and common reed (Phragmites australis) at thirty two sites along the entire lagoon and connected drains. Contamination Factor (CF), Pollution Load Index (PLI), Geo-accumulation Index (Igeo), and Enrichment Factor (EF) were calculated to assess the grade of contamination. Element accumulation factor (AF) and bio-concentration ratio (BCR) were also calculated. Aluminum showed the highest median (mg kg−1) total content (41,200), followed by Fe (30,300), Mn (704.7), V (82.0), Zn (75.5), Cr (51.2), Cu (47.8), Ni (44.3), As (31.9), Tl (24.6), Co (21.4), Se (20.3), Sb (17.6), Sn (15.6), Mo (11.3), and Hg (16.6 μg kg−1). Values of the EF, CF, and Igeo showed that the sediments were heavily contaminated with As, Sb, Se, Tl, Mo, Sn, Co, Ni, and Cu. The drained sediment had significantly higher values of total and potentially available element content than the lagoon sediments. Sediments of the middle and western area showed significantly higher contents of total and available elements than the eastern section. The BCR and AF values indicate that the studied plant is efficient in taking up high amounts of Zn, Fe, As, Sn, Tl, Ni, Mo, Mn; then Co, Cu, and V. The results exhibit a dramatic contamination at certain sites of the lagoon, and the studied PTEs have a predominant role in contamination-related ecological risk. Further investigations concerning redox-induced mobilization of PTEs in sediments, the risk of fish contamination and the potential health hazards are highly recommended