653 research outputs found

    Feasibility of using self-compacting concrete in civil engineering applications

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    This research aimed to investigate the feasibility of using self-compacting concrete in civil engineering applications as a producing a precast hollow unit. The behavior of the hollow sections cast with self-compacted concrete beneath line-load was evaluated. An experimental work was carried out and a finite element model with ANSYS (version 15) was adopted. A total of fourteen hollow beams were cast and tested. The most variables taken into thought were; the types of reinforcement (reinforced steel bar and steel wire meshes), the types of steel wire meshes (expanded and welded steel wire mesh), number of layers of steel meshes (one layer and two layers), cross section thickness of concrete (40 mm and 60mm), concrete cover thickness (15mm and 20 mm) and also the shapes of cross section (square or circular). Special attention to initial cracking load, ultimate load, deflection, cracking pattern, energy absorption and ductility index were investigated. Good agreement was found compared with the experimental results. Out of this research; this paper presents applications of self-compacted concrete for casting skinny structural hollow members. These members can be used as precast units within the construction of the tunnel to decrease the problems in highway roads due to the difficulty of using crossing bridges particularly for kids and old people which are very useful for developing countries with great economic advantages

    Diffusion tensor magnetic resonance imaging : is it valuable in the detection of brain microstructural changes in patients having migraine without aura?

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    Purpose: The aim of this study is to assess the diagnostic value of diffusion tensor magnetic resonance imaging (MRI) in the detection of brain microstructural changes in patients having migraine without aura. Material and methods: Our prospective study included 33 patients having migraine without aura and 15 volunteers with matched age and sex, who underwent brain MRI with diffusion tensor imaging (DTI). The fractional anisotropy (FA) and mean diffusivity (MD) of selected grey and white matter regions on both sides were measured and correlated with the neurological clinical examination. Results: Significant differences were detected in MD values in the thalamus, globus pallidus, and hippocampus head on the right side of patients versus controls. Also, significant differences of the FA values were detected in the thalamus, globus pallidus, and hippocampus head on the right side of patients versus controls. Regarding the FA values of the same regions on the left side, a significant difference in the FA value was detected only in the hippocampus head. There was a statistically significant difference in the FA values on both sides of the white matter of the frontal lobes, posterior limbs of the internal capsules, and cerebellar hemispheres in patients compared to controls. There was a statistically significant difference in MD values in the white matter of both frontal lobes, posterior limb of the right internal capsule, and both cerebellar hemispheres in patients compared to controls. Conclusions: DTI can detect microstructural changes of the grey and white matter in patients having migraine without aura that could not be detected by conventional MRI

    Role of N-terminal pro B-type natriuretic peptide in acute exacerbation of chronic obstructive pulmonary disease

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    AbstractObjectivesAcute exacerbation of chronic obstructive pulmonary disease (AECOPD) is a major public health problem. Recognition of comorbid heart dysfunction in such patients is often difficult. The aim of this work is to evaluate the role of N-terminal pro B-type natriuretic peptide (Nt-pro BNP) in AECOPD with respiratory failure.Patients and methodsThis study was conducted on 20 patients with AECOPD and respiratory failure. All patients were subjected to history taking, clinical examination, routine laboratory investigations, arterial blood gases analysis, echocardiography and estimation of plasma level of NT-pro BNP.ResultsPatients were classified into 3 groups: Group I: those without heart dysfunction (40%), Group II: those with diastolic heart failure (40%), and Group III: those with systolic heart failure (20%). NT-pro BNP mean±SD in group I was 673.38±416.02, in group II 1962±847.88, and in group III 6776.75±1433.59pg/ml. There was a statistically significant difference between the three groups (p=0.001). NT-pro BNP showed a statistically significant inverse correlation with pH (p=0.005), ejection fraction (p=0.007) and a direct one with both left ventricular systolic (p=0.008) and diastolic (p=0.016) dimensions and E/A (p=0.016). The NT-pro BNP significantly decreased after recovery from AECOPD (p=0.030). The receiver operating characteristic curve demonstrated a ruling out of LV dysfunction in AECOPD of a sensitivity of 100% and a specificity of 60%; and a ruling in of a sensitivity of 48% and a specificity of 67%.ConclusionPlasma BNP is usually elevated in AECOPD and is related to right or left ventricular systolic or diastolic dysfunction

    Aroma-loaded microcapsules with antibacterial activity for eco-friendly textile application: synthesis, characterization, release, and green grafting

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    Fragrant and antimicrobial properties were conferred to cotton fabrics following microencapsulation using green materials. Limonene and vanillin microcapsules were produced by complex coacervation using chitosan/gum Arabic as shell materials and tannic acid as hardening agent. The effect of two emulsifiers; Span 85 and polyglycerol polyricinoleate (PGPR), on the encapsulation efficiency (EE%), microcapsule’s size and morphology, and cumulative release profiles was studied. The mean diameter of the produced microcapsules ranged between 10.4 and 39.0 μm, whereas EE% was found to be between 90.4% and 100%. The use of Span 85 resulted in mononuclear morphology while PGPR gave rise to polynuclear structures, regardless of the core material (vanillin or limonene). The obtained microcapsules demonstrated a sustained release pattern; namely the total cumulative release of the active agents after 7 days at 37 ± 1 °C was 75%, 52% and 19.4% for the polynuclear limonene microcapsules, the mononuclear limonene microcapsules and the polynuclear vanillin microcapsules, respectively. Grafting of the produced microcapsules onto cotton fabrics through na esterification reaction using citric acid as a nontoxic cross-linker followed by thermofixation and curing, was confirmed by SEM and FTIR spectroscopy. Standard antibacterial assays conducted on both microcapsules alone and impregnated onto the fabrics indicated a sustained antibacterial activity.info:eu-repo/semantics/publishedVersio

    The impact of pretreatment with simvastatin on kidney tissue of rats with acute sepsis

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    It has been reported that changes in cytokine levels affect mitochondrial functions, levels of hypoxia-inducible factor α (HIF-1α), and tissue damage during sepsis. We aimed to investigate the effects of simvastatin pretreatment on mitochondrial enzyme activities, and on levels of ghrelin, HIF-1α, and thiobarbituric acid reactive substances (TBARS) in kidney tissue during sepsis. Rats were separated into four groups, namely, control, lipopolysaccharides (LPS) (20 mg/kg), simvastatin (20 mg/kg), and simvastatin + LPS. We measured the levels of mitochondrial enzyme activities and TBARS in the kidney using spectrophotometry. The histological structure of the kidney sections was examined after staining with hematoxylin and eosin. Tumor necrosis factor α (TNF-α), IL-10, HIF-1α, and ghrelin immunoreactivity were examined using proper antibodies. In tissue, TNF-α (p  0.05). Ghrelin immunoreactivity was lower in the LPS group (p  0.05). We observed that pretreatment of simvastatin caused favorable changes on ghrelin and TBARS levels in rats with sepsis

    Joint Associations of Activity Energy Expenditure and Sedentary Behaviors with Adolescent's Obesity and Dietary Habits

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    PURPOSE: Physical inactivity and sedentary behaviors are thought to be independent entities and differently associate with adverse health outcomes. Thus, the aim of this study was to investigate the joint associations of physical activity and sedentary behaviors with obesity indices and dietary habits among adolescents from the Gulf Cooperation Council (GCC) countries. METHODS: Data were from the Arab Teens Lifestyle Study (ATLS), a school based, cross-sectional lifestyle study. The present analysis included 6279 adolescents (49.4% males) aged 14-20 years, randomly selected from eight major cities in the GCC countries, using a multistage stratified cluster sampling technique. Anthropometric and self-reported lifestyle data were obtained from participants. Adolescents were classified into four categories: high active & low sedentary (HA-LS), high active & high sedentary (HA- HS), low active & low sedentary (LA-LS) and low active & high sedentary (LA-HS), based on cut off scores of total activity energy expenditure and daily screen time above and below 1680 METs-min/week and above or below 3 hours/day, respectively. RESULTS: Results of MANCOVA tests controlling for age revealed that compared with those with LA-HS, adolescents with HA-LS had signifi cantly (<0.001) lower mean (SD) values for BMI (22.6 (5.5) vs 23.7 (6.2)), waist to height ratio (0.45 (.07) vs 0.48 (.08)), and less frequent intakes of sugar-sweetened drinks (3.7 (2.5) vs 4.5 (2.3)), fast foods (2.2 (1.9) vs 2.9 (1.9)), French fries/potato chips (2.1 (2.0) vs 2.9 (2.1)), cakes/donuts (2.4 (2.1) vs 2.7 (2.1)) and sweets (2.5 (2.1)) vs 3.8 (2.3) but more frequent intakes of breakfast (3.9 (2.7) vs 3.3 (2.6)), vegetables (4.4 (2.3) vs 3.5 (2.4)), fruits (4.2 (2.3) vs 2.8 (2.2)) and milk (4.3 (2.5) vs 3.6 (2.5)). CONCLUSIONS: Adolescents with combined high activity energy expenditure and low sedentary behaviors tend to have lower risk of obesity and have more favorable (healthy) dietary habits. These findings carry important implications for adolescent’s health promotion and obesity prevention.American College of Sports Medicin
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