843 research outputs found

    THE CORRELATION OF MATRIX METALLOPROTEINASE-9 WITH STROKE AND PREVALENCE, RISK FACTORS, AND KNOWLEDGE OF STROKE AMONG PALESTINIANS

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    Objectives: The research study aims to estimate the prevalence of the stroke, to evaluate the stroke associated risk factors, and to determine the factors and symptoms associated with the knowledge of the stroke among the Palestinian population. Furthermore, to find the association between matrix metalloproteinase-9 (MMP-9) levels and the stroke, the concentration of MMP-9 in the serum of stroke patients was measured. Methods: The research study includes a cross-sectional survey that was conducted. The serum MMP-9 levels were also measured in 11 stroke patients using an ELISA reader. Statistical analysis was performed by GraphPad Prism version 8. Sociodemographic characteristics of stroke patients associated with stroke among the Palestinian population were also obtained and analyzed. Results: The higher incidence of the stroke was in the patient’s ages between 51 and 60 years old, with 30 patients (46%) of the total stroke patients. The majority of the stroke patients 40 (60.6%) were having enough income. Most of the stroke patients (29, 43.9%) were none educated. The majority of the stroke patients 48 (72.2%) had a family member/s who has been diagnosed with a stroke. Most of the stroke patients 60 (90.9%) have sudden numbness, weakness in the face, arms, and legs. All the samples analyzed showed a marked increase in MMP-9 concentration. Conclusions: The prevalence of stroke and the high risk of stroke were high among adults aged ≥51 years in Palestine. Hypertension was the highest risk factor for stroke. The serum MMP-9 could be an important prognostic factor for the stroke

    Prevalence of Gall Bladder Stones among Type 2 Diabetic Patients in Benghazi Libya: A Case-control Study

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    Background: Diabetes mellitus and gall bladder stones are both common and costly diseases. Increasing age, female gender, overweight, familial history of the disease and type 2 diabetes mellitus is all associated with an increased risk of gallstones. Several studies from around the world reported an increased prevalence of gall bladder stones in patients with diabetes mellitus. Aims and objectives: The aim of this study was to define the frequency of gall bladder stones among Libyan diabetics and to evaluate the possible associated risk factors in these patients. Patients and methods: A case-control study was performed during 2007 at Benghazi Diabetes and endocrinology Center. The study involved 161 randomly selected type-2 diabetic patients under regular follow up at the center, and 166 age and sex matched non-diabetic outpatients at the 7th of October teaching hospital. Real-time abdominal ultrasound was performed by two radiologists to examine the abdomen after an overnight fast. Results: About 40% of the diabetic cohort had gall bladder stones as compared to 17.5% of non-diabetic patients. Females were significantly more affected than males. Patients with gall bladder stones were significantly older and had a significantly higher body mass index than those without stones. Conclusion: The prevalence of gallstones in Libyan diabetic patients is higher than the rates reported in other parts of the world. Libyan diabetic patients with gallstones tend to be older and more obese than those without gallstones. Duration of diabetes mellitus and type of treatment does not seem to influence the frequency of gall bladder stones among Libyan diabetics

    Internal layers in turbulent free-shear flows

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    The characteristics of the internal layers of intense shear are examined in a mixing layer and in a jet, in the range of Reynolds numbers 134<Reλ<275. Conditionally averaged profiles of streamwise velocity conditioned on the identified internal layers present strong velocity jumps, which account for approximately 10% of the characteristic large-scale velocity of the flow. The thickness ⟨δw⟩ of the internal layers from the combined analysis of both the mixing layer and the jet scales with ⟨δw⟩/λ∼Re−1/2λ, which suggests a scaling with the Kolmogorov length scale (η), analogous to recent observations on the turbulent/nonturbulent interface (TNTI). The thickness of the internal shear layers within the mixing layer is found to be between 9η and 11η. The concentration of a passive scalar across the internal layers is also examined, at the Schmidt number Sc=1.4. The scalar concentration does not show any jumps across the internal layers, which is an important difference between the internal layers and the TNTI. This can be explained from the analysis of the internal layers of intense scalar gradient, where the flow topology node/saddle/saddle dominates, associated with strain, whereas the internal layers of intense shear are characterized by a prevalence of focus/stretching. A topological content analogous to that obtained in layers of intense scalar gradient is found in proximity to the TNTI, at the boundary between the viscous superlayer and the turbulent sublayer. These observations evidence that the TNTI and the internal layers of intense scalar gradient are similar in several respects

    Scale dependence of the alignment between strain rate and rotation in turbulent shear flow

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    The scale dependence of the statistical alignment tendencies of the eigenvectors of the strain-rate tensor ei, with the vorticity vector ω, is examined in the self-preserving region of a planar turbulent mixing layer. Data from a direct numerical simulation are filtered at various length scales and the probability density functions of the magnitude of the alignment cosines between the two unit vectors |ei⋅ˆω| are examined. It is observed that the alignment tendencies are insensitive to the concurrent large-scale velocity fluctuations, but are quantitatively affected by the nature of the concurrent large-scale velocity-gradient fluctuations. It is confirmed that the small-scale (local) vorticity vector is preferentially aligned in parallel with the large-scale (background) extensive strain-rate eigenvector e1, in contrast to the global tendency for ω to be aligned in parallel with the intermediate strain-rate eigenvector [Hamlington et al., Phys. Fluids 20, 111703 (2008)]. When only data from regions of the flow that exhibit strong swirling are included, the so-called high-enstrophy worms, the alignment tendencies are exaggerated with respect to the global picture. These findings support the notion that the production of enstrophy, responsible for a net cascade of turbulent kinetic energy from large scales to small scales, is driven by vorticity stretching due to the preferential parallel alignment between ω and nonlocal e1 and that the strongly swirling worms are kinematically significant to this process.Fluid Mechanic

    Investigation of the generalization capability of a generative adversarial network for large eddy simulation of turbulent premixed reacting flows

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    In the past decades, Deep Learning (DL) frameworks have demonstrated excellent performance in modeling nonlinear interactions and are a promising technique to move beyond physics-based models. In this context, super-resolution techniques may present an accurate approach as subfilter-scale (SFS) closure model for Large Eddy Simulations (LES) in premixed combustion. However, DL models need to perform accurately in a variety of physical regimes and generalize well beyond their training conditions. In this work, a super-resolution Generative Adversarial Network (GAN) is proposed as closure model for the unresolved subfilter-stress and scalar-flux tensors of the filtered reactive Navier-Stokes equations solved in LES. The model trained on a premixed methane/air jet flame is evaluated a-priori on similar configurations at different Reynolds and Karlovitz numbers. The GAN generalizes well at both lower and higher Reynolds numbers and outperforms existing algebraic models when the ratio between the filter size and the Kolmogorov scale is preserved. Moreover, extrapolation at a higher Karlovitz number is investigated indicating that the ratio between the filter size and the thermal flame thickness may not need to be conserved in order to achieve high correlation in terms of SFS field. Generalization studies obtained on substantially different flame conditions indicate that successful predictive abilities are demonstrated if the generalization criterion is matched. Finally, the reconstruction of a scalar quantity, different from that used during the training, is evaluated, revealing that the model is able to reconstruct scalar fields with large gradients that have not been explicitly used in the training. The a-priori investigations carried out assess whether out-of-sample predictions are even feasible in the first place, providing insights into the quantities that need to be conserved for the model to perform well between different regimes, and represent a crucial step toward future embedding into LES numerical solvers
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