288 research outputs found

    Waterjet cutting up to 900 MPa

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    Seismic fragility curves for mid-rise reinforced concrete framed structures with different lateral loads resisting systems

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    The current study presents lateral load analysis of mid-rise reinforced concrete framed structures with two different lateral load resisting systems; shear walls and rigid marginal beams. The main objective here is to investigate the influence of the location of the system in the structure; i.e. arrangement of shear walls and level of the marginal beam. For that purpose, seismic fragility curves are used as an assessment tool for comparing the seismic performance of the studied structures in different situations. Incremental dynamic analysis was performed under ten ground motions to determine the yielding and collapse capacity of each building. Five performance levels were considered in the analysis. These performance levels are (i) operational, (ii) immediate occupancy, (iii) damage control, (iv) life safety and (v) collapse prevention. Fragility curves were developed for the structural models of the studied structures considering the previously mentioned performance levels. It was observed that arrangement of shear walls on the long direction of the structure has insignificant effects on its performance while interior shear walls provide the best behavior of the structure compared to exterior shear walls only and distributing shear walls internally and externally. The analysis outcomes also indicated that the presence of the rigid marginal beam in the lower storey gives more efficiency regarding to lateral loads resistance in the studied structure

    Strengthening of Concrete Beams Using FRP Composites

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    Finite element analysis (FEA) is used to predict the behavior of reinforced concrete beams strengthened with fiber reinforced polymer (FRP). To verify and measure the accuracy of the FEM model, the current model results were compared with both experimental and theoretical available results. Four beams were studied simulating the Horsetail Creek Bridge, Oregon, USA. The first one is a control beam with no strengthening fiber.The second beam is strengthened with carbon fiber reinforced polymer (CFRP) oriented along the length of the beam to reinforce the flexure behavior. The third beam is wrapped with glass fiber reinforced polymer(GFRP) laminates representing the shear beam. The fourth one is strengthened with CFRP and GFRP laminates representing the flexure-shear beam.The load-strain for concrete, steel and fiber as well were represented and compared. In addition, the load deflection curves and crack patterns were developed and represented. The results showed that the modeling process was accurate in simulating the tested beams. It was also clear that using FRP in strengthening reinforced concrete beams is an effective method in improving both shear and flexural behavior of the beams

    The Role of CD 34 Hematopoietic Progenitor Cells, Macrophages, and Smooth Muscle Cells in Human Coronary Artery Atherogenesis

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    BACKGROUND: Atherosclerosis is a widespread and devastating disease and one of the leading causes of death worldwide. So much is there to understand about atherosclerosis. And although a lot is already discovered, yet most of the studies are performed in cell cultures and animal models. Recent technologies for genetic engineering and imaging are mainly performed on animal models, with few studies in human tissues. A better understanding of their role is required. AIM: We aim to study the expression of CD 34 hematopoietic progenitor stem cell, CD 68 macrophages, and smooth muscle actin (SMA)-positive smooth muscle cells (SMCs) in the human coronary arteries and correlate their differential expression with the atherosclerosis progression. RESULTS: CD 68 and CD 34 expression increase as the atherosclerotic process proceeds from early atheroma to advanced atheroma and start to decrease as the process proceeds to fibroatheroma with a significant p < 0.001. Conversely, SMA expression decreases as the atherosclerotic process progresses with a significant p < 0.001. CONCLUSION: CD34 progenitor cells in conjunction with CD 68 macrophages have a major role in the development of atherosclerosis, whereas the SMCs are minimal in the early stages and reach their maximal levels during the stage of fibroatheroma

    Spontaneous ovulation and pregnancy in women with polycystic ovarian disease; a cross sectional study

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    Background: Polycystic ovary disease (PCOD) is the most common endocrine disorder in women of reproductive age, with a prevalence of approximately 5-10%. This study aims to assess the rate of spontaneous ovulation and pregnancy in patients. The present study was a cross sectional study conducted at Woman's Health Hospital, Assiut University, Assiut, Egypt.Methods: The current study was a cross sectional study carried out in Assiut Women's Health Hospital between the 1st October 2016 and 31st July 2017. The patients were selected as infertile patients with PCOD. The patient ages range between 20 and 35 years. The BMI is between 18 and 30 Kg/m2. The main outcome measure was the rate of spontaneous ovulation and spontaneous pregnancy in the 3 cycles.Results: The mean age of the study participants was 26.64±4.59 years and the mean BMI was 24.46±2.62Kg/m2. The sonographic ovarian volume was 12.47±0.69 mm3 for the right ovary and 12.74±0.73 mm3 for the left ovary. No difference in the serum FSH, LH, FSH/LH ratio and prolactin over the 3 consecutive cycles. The rate of spontaneous ovulation in the 3 cycles was 6 women (8.6%) and 2 cases (2.8%) became pregnant spontaneously during the study period. There is no statistical significant difference between ovulating and non-ovulating women according to the BMI and ovarian volume.Conclusions: The present study concluded that the rate of spontaneous ovulation was 8.6% in women with PCOD within 3 cycles with no adverse effects of drugs or surgical interference

    Value of biochemical markers in predicting outcome of COVID-19 infection in University Hospital, Alexandria, Egypt

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    This paper aims to examine the value of different biochemical markers in predicting the outcome of COVID-19 infection. A total of 140 patients with confirmed COVID-19 infection by polymerase chain reaction (PCR), different biochemical markers were tested, their relation to the outcome of the disease was monitored, and the most reliable tests were determined. The study found a significant correlation between all evaluated biochemical markers and severity of the disease, including C-reactive protein (CRP), D-dimer, alanine aminotransferase (ALT), Aspartate aminotransferase (AST), prothrombin time (PT), activated partial thromboplastin time (aPTT). In addition, ferritin, lactate dehydrogenase (LDH), procalcitonin (PCT) and Pro- Brain natriuretic peptide (proBNP) demonstrated highly sensitivity and specificity as well as significant prognostic performance. These markers were also independently significant in predicting mortality. Early assessment of biochemical markers in patients with COVID-19 can help clinicians in tailoring treatment and providing more intensive care to those with greater mortality risk. In particular, the assessment of ferritin, LDH, procalcitonin and proBNP can independently predict mortality

    Adaptive Fuzzy Supplementary Controller for SSR Damping in a Series-Compensated DFIG-Based Wind Farm

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    Although using a series compensation technique in a long transmission line effectively increases the transmittable power; it may cause a sub-synchronous resonance (SSR) phenomenon. Gate-controlled series capacitor (GCSC) is an effective method for SSR damping by controlling the turn-off angle. In the previous studies, a constant supplementary damping controller (SDC) was used for controlling the turn-off angle, which can mitigate the SSR phenomenon. However, these methods can not capture the maximum transmittable power at different operating points. In this paper, a fuzzy logic controller (FLC) is proposed to compute the gain of SDC based on the wind speed and the error between the measured and reference line currents for transferring as much power as possible and damping the SSR phenomenon simultaneously. Using the MATLAB/SIMULINK program, the proposed method is tested at different operating points to validate its effectiveness and robustness. Compared to the traditional method (constant SDC), the maximum transmittable power, as well as SSR damping, is achieved in all studied cases by the proposed method (variable SDC)

    Soluble egg antigen of Schistosoma Haematobium induces HCV replication in PBMC from patients with chronic HCV infection

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    BACKGROUND: This study was conducted to examine, in vitro , the effect of soluble egg antigen (SEA) of S. haematobium on intracellular HCV RNA load in peripheral mononuclear cells (PBMC) as well as on cell proliferation in patients with chronic HCV infection. METHODS: PBMC from 26 patients with chronic HCV infection were cultured for 72 hours in presence and absence of 50 μg SEA/ml medium. Intracellular HCV RNA quantification of plus and minus strands was assessed before and after stimulation. PBMC from five healthy subjects were cultured for 7 days, flow cytometric analysis of DNA content was used to assess the mitogenic effect of SEA on PBMC proliferation compared to phytoheamaglutinine (PHA). RESULTS: Quantification of the intracellular viral load showed increased copy number/cell of both or either viral strands after induction with SEA in 18 of 26 patients (69.2%) thus indicating stimulation of viral replication. Flow cytometric analysis showed that mean ± S.D. of percent values of cell proliferation was induced from 3.2 ± 1.5% in un-stimulated cells to 16.7 ± 2.5 % and 16.84 ± 1.7 % in cells stimulated with PHA and SEA respectively. CONCLUSION: the present study supports earlier reports on SEA proliferative activity on PBMC and provides a strong evidence that the higher morbidity observed in patients co-infected with schistosomiasis and HCV is related, at least in part, to direct stimulation of viral replication by SEA
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