Computation of compressible quasi-axisymmetric slender vortex flow and breakdown

The unsteady, compressible Navier-Stokes equations are used to compute and analyze compressible quasi-axisymmetric isolated vortices. The Navier-Stokes equations are solved using an implicit, upwind, flux difference splitting finite volume scheme. The developed three dimensional solver was verified by comparing its solution profiles with those of a slender, quasi-axisymmetric vortex solver for a subsonic, quasi-axisymmetric vortex in an unbounded domain. The Navier-Stokes solver is then used to solve for a supersonic, quasi-axisymmetric vortex flow in a configured circular duct. Steady and unsteady vortex-shock interactions and breakdown were captured. The problem was also calculated using the Euler solver of the same code; the results were compared with those of the Navier-Stokes solver. The effect of the initial swirl was investigated

Supersonic quasi-axisymmetric vortex breakdown

An extensive computational study of supersonic quasi-axisymmetric vortex breakdown in a configured circular duct is presented. The unsteady, compressible, full Navier-Stokes (NS) equations are used. The NS equations are solved for the quasi-axisymmetric flows using an implicit, upwind, flux difference splitting, finite volume scheme. The quasi-axisymmetric solutions are time accurate and are obtained by forcing the components of the flowfield vector to be equal on two axial planes, which are in close proximity of each other. The effect of Reynolds number, for laminar flows, on the evolution and persistence of vortex breakdown, is studied. Finally, the effect of swirl ration at the duct inlet is investigated

Nutrition in diabetes

Medical nutrition therapy (MNT) is a key component of diabetes management. The importance of balancing macronutrients, reducing carbohydrate load, lowering glycemic index, and implementing an overall healthy dietary pattern are emerging as better approaches for MNT in diabetes. Recent research points to improved glycemic control, reduction in body weight, and improvement in many cardiovascular risk factors when these approaches are provided by registered dietitians or health care providers. This review article discusses the current evidence about the role of sensible nutrition in diabetes management. Specific eating plans for weight reduction and for patients with type 1 diabetes are also discussed

L-arginine pretreatment ameliorates Lipopolysaccharide-induced thyroid gland dysfunction in male albino rats

Bacterial infection is one of the most common causes of systemic inflammatory syndrome known as sepsis. Previous studies have been shown that sever sepsis was often complicated with secondary multiple organs dysfunction. This syndrome may greatly affect thyroid gland function leading to thyroid gland dysfunction. The objective of this study was to elucidate the effect of bacterial endotoxin (lipopolysaccharide, LPS) on thyroid gland function. The study extended to investigate the role of L-arginine (L-Arg) as immunomodulator in LPS-induced systemic inflammation. Eighty adults, male Wistar rats were randomly divided into four equal groups: The control group was intraperitoneally (IP) injected with physiological sterile saline (0.9% NaCl at dose 1 ml/kg body weight (BW)); LPS-treated group was injected with a single dose of LPS (1 mg/kg BW, IP); L-Argtreated group was injected with L-Arg (10 mg/kg BW, IP) once per day for 7 consecutive days; and L-Arg + LPS treated group was injected with L-Arg (10 mg/kg BW, IP) once per day for 7 consecutive days followed by a single dose of LPS (1 mg/kg BW, IP). Histopathological changes of thyroid gland, serum triiodothyronine (T3), thyroxine(T4), and thyroid stimulating hormone (TSH) levels were examined at 6, 12, 24 and 72 hours (h) after the last injection. Treatment of rats with a single dose of LPS alone resulted in thyroiditis which manifested by decreased serum T3 and T4 levels and severe necrosis of the thyroid follicles. However, in L-Arg-treated endotoxemic rats, pretreatment with L-Arg attenuated the LPS-induced acute thyroid gland injury

Encryption Efficiency Analysis and Security Evaluation of RC6 Block Cipher for Digital Images

This paper investigates the encryption efficiency of RC6 block cipher application to digital images, providing a new mathematical measure for encryption efficiency, which we will call the encryption quality instead of visual inspection, The encryption quality of RC6 block cipher is investigated among its several design parameters such as word size, number of rounds, and secret key length and the optimal choices for the best values of such design parameters are given. Also, the security analysis of RC6 block cipher for digital images is investigated from strict cryptographic viewpoint. The security estimations of RC6 block cipher for digital images against brute-force, statistical, and differential attacks are explored. Experiments are made to test the security of RC6 block cipher for digital images against all aforementioned types of attacks. Experiments and results verify and prove that RC6 block cipher is highly secure for real-time image encryption from cryptographic viewpoint. Thorough experimental tests are carried out with detailed analysis, demonstrating the high security of RC6 block cipher algorithm. So, RC6 block cipher can be considered to be a real-time secure symmetric encryption for digital images

NUMERICAL INVESTIGATION OF THE PERFORMANCE OF INSULATED FRP-STRENGTHENED REINFORCED CONCRETE BEAMS IN FIRE

Fiber reinforced polymers (FRP) have been widely used in retrofitting and strengthening of deteriorated or deficient reinforced concrete (RC) elements. A major concern about those systems is their performance under elevated temperature which limits the application of FRP for strengthening requirements. Fire protection of the strengthening FRP system can be made by applying an external coating layer of a thermal resisting material. In order to predict the fire performance of such insulated FRP-strengthened members and their efficiency, experimental investigations are required to be carried out for such elements under realistic fire conditions, which requires time and cost. This paper presents numerical modelling of RC beams strengthened with externally bonded FRP and insulated by a fire protection layer under elevated temperature specified by standard fire tests. The nonlinear time domain transient thermal-stress finite element analysis is performed using the general purpose software ANSYS 12.1 in order to study the heat transfer mechanism and deformation within the beam for fire conditions initiating at the bottom side of the beam. The finite element model accounts for the variation in thermal and mechanical parameters of the constituent materials such as concrete, steel reinforcement bars, FRP and insulation material with temperature. Application is made on an FRP-strengthened and insulated RC T-beam which has been experimentally tested in the published literature in order to verify the adopted modelling procedure. The obtained numerical results are in good agreement with the experimental results regarding the temperature distribution across the beam and mid-span deflection. The presented procedure thus provides an economical and effective tool to investigate the effectiveness of fire insulation layers when subjected to high temperatures and to design thermal protection layers for FRP strengthening systems that satisfy fire resistance requirements specified in building codes and standards

Young Hispanics at risk of type 2 diabetes display endothelial activation, subclinical inflammation and alterations of coagulation and fibrinolysis

Background: Hispanics have a high rate of diabetes that exposes them to an increased risk of cardiovascular disease. We hypothesized that many of the pathophysiological mechanisms that cause atherosclerotic disease may be present in young Hispanics who do not have clinical diabetes but are at increased risk of developing it. Methods: We studied 36 young Hispanic adults without diabetes (ages 18–40). Seventeen participants were at increased risk of developing type 2 diabetes given by overweight and a family history of diabetes on one or both parents (at risk group). Nineteen participants with normal body-mass index and no parental history of diabetes constituted the control group. We measured and compared plasma markers of endothelial dysfunction, disturbed coagulation and fibrinolysis, subclinical inflammation and adipose tissue dysfunction in the at risk and control groups. Results: Participants at risk of diabetes were more insulin-resistant according to different indicators, and had significantly higher levels of soluble intercellular adhesion molecule-1 (sICAM-1), tissue plasminogen activator (tPA), inhibitor of plasminogen activator-1 (PAi-1), high sensitivity C-reactive protein and free fatty acids, signaling the presence of multiple proatherogenic alterations despite the absence of overt diabetes. Levels of the prothrombotic molecule PAi-1 were most elevated in participants who were not only at risk of diabetes by the study definition, but also abdominally obese. Conclusions: Young adult Hispanics at risk of type 2 diabetes but without overt disease already bear considerably high levels of markers reflecting processes that lead to the development of atherosclerotic cardiovascular disease

Epidemiology of and Risk Factors for Type 2 Diabetes in Egypt

Background: Diabetes is a fast-growing health problem in Egypt with a significant impact on morbidity, mortality, and health care resources. Currently, the prevalence of type 2 diabetes (T2D) in Egypt is around 15.6% of all adults aged 20 to 79. Objective: To describe the epidemiology, principal causes, associated risk factors, cultural aspects, and challenges that may contribute to the rapid rise in T2D in Egypt. Methods: Review of papers in PubMed and relevant gray literature. Findings: The International Diabetes Federation (IDF) has identified Egypt as the ninth leading country in the world for the number of patients with T2D. The prevalence of T2D in Egypt was almost tripled over the last 2 decades. This sharp rise could be attributed to either an increased pattern of the traditional risk factors for T2D such as obesity and physical inactivity and change in eating pattern or other risk factors unique to Egypt. These include increased exposure to environmental risk factors like pesticides and increased prevalence of chronic hepatitis C.. Conclusions: Prevention, early identification, and effective intervention are integral components of effective T2D care in Egypt. These strategies may reduce the expanding economic burden associated with T2D care

Higher nitric oxide levels are associated with disease activity in Egyptian rheumatoid arthritis patients

AbstractBackgroundOxidative stress generated within inflammatory joints can produce autoimmune phenomena and joint destruction. Radical species with oxidative activity, including reactive nitrogen species, represent mediators of inflammation and cartilage damage.ObjectivesTo assess serum nitric oxide as a marker of oxidative stress in Egyptian patients with rheumatoid arthritis and its relation to disease activity.MethodsEighty patients with rheumatoid arthritis were divided into 2 groups, according to the DAS-28 score: Group I: 42 patients with disease activity, and Group II: 38 patients with no disease activity. Forty age- and sex-matched individuals were included as control group (Group III). Routine laboratory investigations were done, and nitric oxide was measured using Elisa. Hand plain radiographies were done for radiological status scoring using the Sharp method.ResultsA comparison between nitric oxide in all three groups showed a highly significant difference (p < 0.001), significantly higher levels were obtained among rheumatoid arthritis patients in comparison to controls, and higher levels were obtained in patients with active disease (mean±SD 82.38±20.46) in comparison to patients without active disease (35.53±7.15). Nitric oxide in Group I showed a significant positive correlation with morning stiffness (r=0.45), arthritis (r=0.43), platelet count (r=0.46), erythrocyte sedimentation rate (r=0.83), C-reactive protein (r=0.76) and Disease Activity Score (r=0.85). Nitric oxide showed a significant positive correlation (r=0.43) with hand radiographies (Sharp score) in Group I.ConclusionThere are increased levels of nitric oxide in the serum of patients with rheumatoid arthritis. Nitric oxide correlates significantly with disease activity, inflammatory markers and radiological joint status

Hiding data in images using steganography techniques with compression algorithms

Steganography is the science and art of secret communication between two sides that attempt to hide the content of the message. It is the science of embedding information into the cover image without causing a loss in the cover image after embedding.Steganography is the art and technology of writing hidden messages in such a manner that no person, apart from the sender and supposed recipient, suspects the lifestyles of the message. It is gaining huge attention these days as it does now not attract attention to its information's existence. In this paper, a comparison of two different techniques is given. The first technique used Least Significant Bit (LSB) with no encryption and no compression. In the second technique, the secret message is encrypted first then LSB technique is applied. Moreover, Discrete Cosine Transform (DCT) is used to transform the image into the frequency domain. The LSB algorithm is implemented in spatial domain in which the payload bits are inserted into the least significant bits of cover image to develop the stego-image while DCT algorithm is implemented in frequency domain in which the stego-image is transformed from spatial domain to the frequency domain and the payload bits are inserted into the frequency components of the cover image.The performance of these two techniques is evaluated on the basis of the parameters MSE and PSNR