nasser hamdy

Chronic low back pain (LBP) is an extremely common problem in practice, where it is often labeled idiopathic. No sufficient studies have been conducted to analyze the contribution of hypovitaminosis D to the etiology of chronic LBP in populations wherein vitamin D deficiency is endemic. The present study was, therefore, carried out to examine hypovitaminosis D and its determinants in female patients with chronic LBP during the childbearing period. Sixty female patients complaining of LBP lasting more than 3 months were clinically studied rheumatologically and neurologically. Questionnaires and indices quantifying risk factors associated with vitamin D deficiency were utilized. Biochemical assays of serum calcium, phosphorus, alkaline phosphatase (ALP), parathormone (PTH), and 25-hydroxyvitamin D (25 OHD) were performed and compared to those of 20 matched healthy controls. The determinants of vitamin D levels in patients were examined by stepwise regression. Patients with LBP had significantly lower 25 OHD levels (p < 0.05) and significantly higher PTH (p < 0.05) and ALP (p < 0.001) than controls, although there were no significant group differences in calcium and phosphorus. Hypovitaminosis D (25 OHD < 40 ng/ml) was found in 49/60 patients (81%) and 12/20 (60%) of controls, with an odds ratio of 2.97. Although many risk factors related to sun exposure, clothing, diet, and pregnancy were significantly correlated with vitamin D levels in patients, only limited duration of sun exposure, contributing 55% to the variance of 25 OHD, limited areas of skin exposed (13%), and increased number of pregnancies (2%), were significant determinants of vitamin D levels in patients. Despite the sunny climate, hypovitaminosis D is prevalent among Egyptian women in the childbearing period, especially those presenting with chronic LBP, where it is associated with hyperphosphatasia and hyperparathyroidism, without alterations in serum calcium. The major determinant of hypovitaminosis D in our patients is limited sun exposure.

In Plasma physics, nonlinear ion acoustic waves are shown to bedescribed by the Korteweg-de-Vries equation. When the drag force actedby the waves on the particles is taken into consideration, the governingequation is shown to be a generalized Korteweg-de-Vries equation. TheIntegrability properties of this equation are discussed. Some exactsolutions for this equation are derived by using the techniques of auto-Bäcklund transformation and polynomial invariants.

... DOI: 10.1080/01495730802637233 Magdy A. Ezzat a &amp;amp; ... The earlier authors who considered the generalized magneto-thermoelasticity equations are Nayfeh and Nasser [66. A. Nayfeh and S. Nemat-Nasser , Electromagneto-Thermoelastic Plane Waves in Solids with Thermal ...

The water level fluctuations and geomorphology of Lake Nasser reservoir in Tushka area, Egypt, has its own bearing on the local hydrogeological regime. Comparison of the available data concerning the submerged bottom elevations of Lake Nasser with the static water levels of the groundwater wells reaching the deeper horizons of the Nubia Sandstone aquifer, suggests that Lake Nasser acts mostly as an influent stream. However, in some cases, when the static water levels of some deep water-bearing horizons reach levels above those at the bottom of the lake, water flows from the groundwater reservoirs towards the river which acts as an effluent stream. The constructed equipotentiometric map confirms this conclusion as it indicated that the maximum potentiometric level was attained to the northwestern part of Lake Nasser area, whereas the minimum potentiometric level was encountered to the southeast of this area. Hence, the groundwater flow is generally towards Lake Nasser. However, in some instances, it also flows in an adverse direction. The Piper trilinear diagram revealed the existence of four hydrochemical facies reflecting the quality of the fresh water of Lake Nasser, the slightly saline original water quality of the Nubia aquifer and the mixing facies with no dominant water types. Les fluctuations du niveau d'eau ainsi que la géomorphologie du réservoir du lac Nasser dans la région de Tushka, Egypte influencent le régime hydrogéologique local. La comparaison de l'altitude des fonds du lac Nasser avec les niveaux phréatiques des puits qui atteignent les niveaux inférieurs de l'aquifère des grès Nubiens suggère que le lac Nasser agisse le plus souvent comme un cours d'eau infiltrant. Il arrive aussi, lorsque le niveau hydrostatique d'horizons aquifères profonds dépasse ceux de la base du lac, que l'eau des aquifères soutienne les eaux de la rivière qui agit alors comme un émissaire. Les cartes hydro isostatiques confirment cette conclusion en indiquant que le niveau maximum est atteint au Nord-Ouest de la région du lac Nasser et que le niveau minimum se trouve au Sud-Est de cette zone. Ainsi, les eaux souterraines se dirigent généralement en direction du lac Nasser. Mais, elles se dirigent parfois en direction inverse. Le diagramme de Piper montre l'existence de quatre faciès hydro chimiques, qui correspondent à l'eau douce du lac Nasser, à l'eau légèrement salée de l'aquifère Nubien, et les eaux mélangées sans types d'eaux dominants. Las fluctuaciones del nivel de agua y la geomorfología del reservorio del Lago Nasser en el área de Tushka, Egipto, tienen su propia influencia sobre el régimen hidrogeológico local. La comparación de los datos disponibles acerca de las elevaciones del fondo sumergido de Lago Nasser, con los niveles estáticos de los pozos de agua subterránea que alcanzan los horizontes más profundos del acuífero de la Arenisca de Nubia, sugieren que el Lago Nasser actúa principalmente como una corriente influente. Sin embargo, en algunos casos, cuando los niveles estáticos de agua de algunos horizontes acuíferos profundos, alcanzan niveles por encima de aquellos del fondo del lago, el agua fluye desde los depósitos de agua subterránea hacia el río, que actúa entonces como una corriente efluente. El mapa equipotenciométrico construido confirma esta conclusión, pues indica que el nivel potenciométrico máximo estaba localizado en la parte noroccidental del área del Lago Nasser, mientras que el nivel potenciométrico mínimo se encontró al sudeste de esta área. Por lo tanto, el flujo del agua subterránea generalmente va hacia el Lago Nasser. Sin embargo, en algunos casos, también fluye en una dirección contraria. El diagrama trilinear de Piper, reveló la existencia de cuatro facies hidroquímicas que reflejan la calidad de agua dulce del Lago Nasser, la calidad de agua ligeramente salina original del acuífero de Nubia y las facies mezcladas sin tipos de agua dominantes.

... Hany H. Sherief a &amp;amp; Hamdy M. Yosef a pages 537-559. ... (11), we get. Equation (2) in our case takes the form. For simplification, we shall use the following nondimensional variables: where. The preceding equations reduce to (dropping the asterisks for convenience). where. ...