Showing papers by "Cairo University published in 1998"

Uterine myomata and outcome of assisted reproduction.

Abstract: The aim of this work was to study the effect of uterine myomata on the implantation rate and outcome in in-vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) Among 406 patients, 51 (126%) were found to have uterine corporeal myomata Twelve patients were excluded from the study as they had large myomata, submucous myomata or intramural myomata encroaching on the cavity These patients were advised to have myomectomy before being enrolled in the IVF/ICSI programme The remaining patients (n = 39) were sorted according to the number, site and size of the myomata as assessed by transvaginal sonography Three patients had more than one myoma Most of the myomata were subserous (727%) and the mean diameter of the myomata was 35 +/- 09 cm A control group (n = 367) was chosen with normal uteri and no history of uterine reconstruction surgery The mean age of myoma patients was 347 +/- 36 years as compared to 340 +/- 44 years in the control group The age, period of infertility, body mass index, duration and number of human menopausal gonadotrophin ampoules needed for stimulation, oestradiol levels, number of oocytes retrieved and the fertilization rate were not significantly different in the myoma patients compared to the control group Fifteen myoma patients (385%) subsequently showed one or more pregnancy sacs on ultrasonography of which three (20%) spontaneously aborted during the first trimester and two (133%) had preterm labour, as compared to 123 (335%), 19 (155%) and nine (73%) respectively, among the control group (P = 027, 033 and 021) In conclusion, uterine corporeal myomata, not encroaching on the cavity and <7 cm in mean diameter, do not affect the implantation or miscarriage rates in IVF or ICSI

Using neural networks in the identification of Preisach-type hysteresis models

Abstract: The identification process of the classical Preisach-type hysteresis model reduces to the determination of the weight function of elementary hysteresis operators upon which the model is built. It is well known that the classical Preisach model can exactly represent hysteretic nonlinearities which exhibit wiping-out and congruency properties. In that case, the model identification can be analytically and systematically accomplished by using first-order reversal curves. If the congruency property is not exactly valid, the Preisach model can only be used as an approximation. It is possible to improve the model accuracy in this situation by incorporating more appropriate experimental data during the identification stage. However, performing this process using the traditional systematic techniques becomes almost impossible. In this paper, the machinery of neural networks is proposed as a tool to accomplish this identification task. The suggested identification approach has been numerically implemented and carried out for a magnetic tape sample that does not possess the congruency property. A comparison between measured data and model predictions suggests that the proposed identification approach yields more accurate results.

Soil and plant analysis as a guide for interpretation of the improvement efficiency of organic conditioners added to different soils in Egypt

Abstract: Four local organic conditioners:biogas residues (precipitates), poultry manure, sewage sludge and composted town refuse were subjected to an experiment aimed at evaluation their efficiency for improvement the physical and chemical properties of four soils that known at El‐Fayoum area as soils below the production levels. The tested soils were alluvial clay from the Faculty Farm at Dar El‐Ramad, highly calcareous loamy sand from the Faculty Farm at Demo, calcareous sandy loam from Kom Osheem village and heavy clay from Kassr Rashwan village. With each of the tested soils, treatments comprised each of the above mentioned organic conditioners at increasingly levels depending on its carbon/nitrogen (C/N) ratio were performed. Then, the treatments were subjected to a pot experiment cropped with wheat plants under greenhouse conditions. With each treatment, determinations of the soil physical properties (saturation percentage, field capacity, bulk density, total porosity, and hydraulic conductivity) an...

Investigation of scalar mixing in the thin reaction zones regime using a simultaneous CH-LIF/Rayleigh laser technique

Abstract: Simultaneous two-dimensional CH-LIF/Rayleigh measurements were carried out in highly stretched turbulent premixed stoichiometric methane-air flames. These flames fall into the thin reaction zones regime. In this regime, the Kolmogorov scale is smaller than the preheat zone thickness of a laminar flame, but it is larger than the reaction zone thickness. Therefore, small eddies can penetrate into the preheat zone but not into the reaction zone. These small eddies widen the preheat zone by turbulent mixing. In the present flames at Karlovitz numbers Ka of 23 and 91, thin reaction zones with relatively thick turbulent preheat zones are being observed. The thickness of the preheat zone is expected to scale with the mixing length scale lm, which is the thickness of an eddy within the inertial range that has a turnover time equal to the flame time. The temperature/CH images are presented at different axial locations together with line profiles through the reaction zone to illustrate the different structures. In addition probability density functions (PDFs), of temperature conditioned on CH are presented. The present data show that the temperature in the thin reaction zones' regime at the early positions in the highly stretched flames is relatively low. This is attributed to heat loss to the burner. In addition, in highly stretched flames at the borderline of this regime, local extinction has sometimes been observed, which could be due to entrainment of small eddies into the reaction zone.

Global-vector representation of the angular motion of few-particle systems II

Abstract: The angular motion of a few-body system is described with global vectors which depend on the positions of the particles. The previous study using a single global vector is extended to make it possible to describe both natural and unnatural parity states. Numerical examples include three- and four-nucleon systems interacting via nucleon-nucleon potentials of AV8 type and a 3α system with a nonlocal αα potential. The results using the explicitly correlated Gaussian basis with the global vectors are shown to be in good agreement with those of other methods. A unique role of the unnatural parity component, caused by the tensor force, is clarified in the 0− 1 state of 4He. The two-particle correlation function is calculated in the coordinate and momentum spaces to show different characteristics of the interactions employed.

Bäcklund Transformations and Exact Solutions for Alfvén Solitons in a Relativistic Electron–Positron Plasma

Abstract: Nonlinear Alfven waves, propagating along a homogeneous magnetic field, are studied using relativistic isotropic hydrodynamics. Alfven solitons of the moving-wave and wave packet types are considered for modified Korteweg–de Vries (mKdV) equation and the nonlinear Schrodinger (NLS) equation, respectively. The method of characteristics is used and the Backlund transformations (BTs) are employed to generate new solutions from the old ones. Thus, families of new solutions for the mKdV and the NLS equations are obtained. The question arises which solitons exist in the pulsar atmosphere.

Hypermobility among Egyptian children: prevalence and features.

Abstract: Objective. To determine the prevalence, clinical manifestations, and possible associated features of hypermobility among Egyptian children in a prospective study. Methods. Nine hundred ninety-seven healthy children from 4 different educational areas for primary and presecondary schools were screened for the presence of hypermobility. A hypermobility score was used to denote the degree of laxity. Sites and possible clinical associations of hypermobility were determined. Results. The presence of hypermobility was 16.1% among Egyptian children. Hypermobility was more frequent among girls (18%), than boys (14.4%), although the difference was not statistically significant. Age was inversely correlated with the frequency of hypermobility (r = -0.967, p < 0.001) and degree of joint laxity (r = -0.789, p < 0.01). Hypermobility was most prevalent in fingers (96.9%) and least prevalent in knee joints (3.1%). Hypermobility was statistically more frequent in nondominant than dominant fingers (p < 0.002). Arthralgia. high palate. flat feet. Raynaud's phenomenon. and easy bruising were more common among the hypermobility group. Conclusion. Our results suggest that hypermobility is not uncommon among Egyptian children. Increased awareness of the condition is needed among pediatricians and other concerned physicians.

Studies on Some Schiff Base Complexes of CoII, NiII and CuII Derived from Salicylaldehyde and O-Nitrobenzaldehyde

Abstract: Schiff bases of the type salicylidene 2-aminobenzothiazole and o-nitrobenzylidene 2-aminobenzothiazole were prepared by condensation of 2-aminobenzothiazole with salicylaldehyde and o-nitrobenzaldehyde. The bases react with cobalt(II), nickel(II) and copper(II) chlorides to give 1:1 and 1:2 complexes. Electronic spectra, magnetic susceptibility measurements and infrared data are used to infer the structures. The thermal decomposition of the complexes and evaluation of the thermodynamic parameters are also reported.

A mesh-free method for linear diffusion equations

Abstract: A ‘mesh-fre’ and ‘time-free’ numerical method, based on the method of fundamental solutions, the dual reciprocity method ( DRM) for the modified Helmholtz operator, and the Laplace transform, has been developed lo solve diffusion-type and diffusion-reaction problems. Our proposed method has achieved both excellent accuracy and efficiency, as illustrated by two numerical examples, in two dimensions and three dimensions. Another attractive feature of our proposed method is the easy implementation for the 3D problems.

Grain surface chemistry: modified models

Abstract: The rate equation approach to the chemistry occurring on grain surfaces in interstellar clouds has been criticized for not taking the discrete nature of grains into account. Indeed, investigations of simple models show that results obtained from rate equations can be significantly different from results obtained by a Monte Carlo procedure. Some modifications of the rate equations have been proposed that have the effect of eliminating most of the differences with the Monte Carlo procedure for simplified models of interstellar clouds at temperatures of 10 K and slightly above. In this study we investigate the use of the modified rate equations in more realistic chemical models of dark interstellar clouds with complex gas-grain interactions. Our results show some discrepancies between the results of models with unmodified and modified rate equations; these discrepancies are highly dependent, however, on the initial form of hydrogen chosen. If the initial form is mainly molecular, at early stages of cloud evolution there are some significant differences in calculated molecular abundances on grains, but at late times the two sets of results tend to converge for the main components of the grain mantles. If the initial form is atomic hydrogen, there are essentially no differences in results between models based on the unmodified rate equations and those based on the modified rate equations, except for the abundances on grains of some minor complex molecules. Thus, the major results of previous gas-grain models of cold, dark interstellar clouds remain at least partially intact.

Utilization of Soda Glass (Cullet) in the manufacture of wall and floor tiles

Abstract: Ground Soda Glass (cullet) (SG) was utilized as an additive to a well blended mixture composed of orthoclase feldspar, quartz, grog and three types of local kaolins from three different sites in Egypt. All the used raw materials, including SG, were fully assessed chemically, thermally and mineralogically. SG was added in gradual proportions in order to study the effect of its addition on the physical properties of fired samples (water absorption, bulk density and apparent porosity). The samples were moulded under 20.7 M Pa and fired at temperatures ranging from 950 to 1100 °C, starting with 3 h as firing time, then decreased to 2 or even 1 h. Both XRD and microscopic investigations (either by polarizing microscope or scanning electron microscope) were used to identify the present phases and degree of vitrification. The results were interpreted due to the presence of liquid glassy phase. The composition containing 23% SG and fast fired at 1100 °C for 3 h had the best mechanical strength. The composition containing 33.3% SG, and fast fired for 1 h at 1100 °C was recommended for non-glazed floor tiles. Standard tests were performed on this composition in the form of tiles and the obtained results were compatible with standard values. Finally, the use of SG was recommended as an additive for its economical potential.

Investigation of flame broadening in turbulent premixed flames in the thin-reaction-zones regime

Abstract: A two-plane two-dimensional Rayleigh thermometry technique is applied to investigate, the three-dimensional flame structure in highly stretched turbulent premixed flames beyond the flamelet regime Experimental data of the preheat zone thickness, σ F , and flame temperature conditioned at the maximum temperature gradient, T o , are reported Broadening of the preheat zone thickness is observed and found to be correlated well with the increase of turbulence intensity This suggests a pure hydrodynamic straining effect in a chemically inert preheat zone in the thin-reaction-zones regime, which is consistent with the rate-ratio asymptotic analysis Although a general decrease of T o is also found with increasing flame stretch, this temperature drop is subject to the nonadiabatic condition in the postflame region Flame extinction would be expected when T o is approaching the ignition temperature ≥900 K

A new concept of the anatomy of the anal sphincter mechanism and the physiology of defecation. Mass contraction of the pelvic floor muscles

Abstract: We have previously demonstrated both anatomically and physiologically that the external anal (EAS) and urethral (EUS) sphincters and the bulbocavernosus muscle (BC) originate from the puborectalis muscle (PR). It is hypothesized that stimulation of any of these muscles would lead to contraction of all the others. Because the levator ani (pubococcygeus) muscle (LA) also has the same innervation as the above-mentioned muscles, it is further suggested that it, too, contracts reflexly upon stimulation of any of those muscles. The purpose of this study was to test this hypothesis. The study comprised 18 healthy volunteers (mean age 36.6 +/- 8.4 years; 10 men, 8 women). The EAS was stimulated and the response of the EUS, PR, LA and BC was determined. Each muscle was thereafter stimulated separately and the response of the other pelvic floor muscles registered. Stimulation of any of the pelvic floor muscles effected an increased EMG activity of the rest of the muscles. The muscle contraction was instantaneous with no latency in all the muscles except the LA EMG activity, which showed a mean latency of 21.3 +/- 6.6 ms. The pelvic floor muscles' response seems to be attributable to muscle stimulation both directly and indirectly through activation of pudendal nerve fibers in the muscles. The study demonstrated that the pelvic floor muscles behave as one muscle: they contract or relax en masse. This 'mass contraction' might explain some of the physiologic phenomena that occur during pelvic organ evacuation. However, besides this mass contraction, a voluntary 'selective' individual muscle activity exists by which each individual muscle acts independently of the others.

Prevalence of hepatitis B and C in Egypt and Africa.

Abstract: Hepatitis B and C are, and will remain for some time, major health problems in Egypt and the entire continent of Africa. Both infections can lead to an acute or silent course of liver disease, progressing from liver impairment to cirrhosis and decompensated liver failure or hepatocellular carcinoma (HCC) in a 20-30 year period. In addition, hepatitis B and C infection rates differ in different settings, and prognosis may be worse in conjunction with schistosomiasis in Egypt, malaria in Sudan and human immunodeficiency virus (HIV) in other African populations. Unlike hepatitis B virus (HBV), for which the prospects for controlling the spread of infection by vaccination are promising, prospects for development of an effective vaccine against hepatitis C virus (HCV) are limited. As well as screening of blood for transfusion and using sterile needles for injection, preventive measures should be undertaken to reduce the risk of contact (often described as community-acquired infection). Until more is known about the unidentified routes of transmission in tropical and subtropical settings it will be difficult to be specific about the kind of measures which may be effective. Success may largely depend on changing habits within the population. Prevention should be the main goal of current efforts until low-cost, effective therapies become available.

Botulin Toxin in the Treatment of Nonrelaxing Puborectalis Syndrome

Abstract: Purpose: To evaluate the results of botulin toxin injection in the external anal sphincter for the treatment of nonrelaxing puborectalis syndrome. Method: 15 pati

Pharmacokinetics of florfenicol in normal and Pasteurella-infected Muscovy ducks.

Abstract: 1. Disposition kinetics of florfenicol were studied in Pasteurella-free (control) and Pasturella-infected Muscovy ducks following intravenous and/or intramuscular injection in a single dose of 30 mg/kg body weight. In addition, the tissue distribution and residual pattern of the drug were determined in diseased ducks. 2. The maximum serum concentration of florfenicol in control healthy and infected ducks was reached 1 hour after intramuscular injection but the peak concentration in control ducks was higher than in infected birds. 3. The volume of distribution, total body clearance and systemic bioavailability were higher in infected ducks than in control birds 5.15 l/kg, 10.24 ml/kg/min and 73.03% respectively. Data relating to intravenous injection were analysed using a 2 compartment open model curve fit. 4. Florfenicol was not detected in the serum of infected ducks on the 7th day following intramuscular administration of 30 mg/kg body weight twice daily for 5 successive days but was detected in kidney, bile and liver.