Showing papers by "Cairo University published in 2002"
TL;DR: A novel algorithm for fuzzy segmentation of magnetic resonance imaging (MRI) data and estimation of intensity inhomogeneities using fuzzy logic and the neighborhood effect acts as a regularizer and biases the solution toward piecewise-homogeneous labelings.
Abstract: We present a novel algorithm for fuzzy segmentation of magnetic resonance imaging (MRI) data and estimation of intensity inhomogeneities using fuzzy logic. MRI intensity inhomogeneities can be attributed to imperfections in the radio-frequency coils or to problems associated with the acquisition sequences. The result is a slowly varying shading artifact over the image that can produce errors with conventional intensity-based classification. Our algorithm is formulated by modifying the objective function of the standard fuzzy c-means (FCM) algorithm to compensate for such inhomogeneities and to allow the labeling of a pixel (voxel) to be influenced by the labels in its immediate neighborhood. The neighborhood effect acts as a regularizer and biases the solution toward piecewise-homogeneous labelings. Such a regularization is useful in segmenting scans corrupted by salt and pepper noise. Experimental results on both synthetic images and MR data are given to demonstrate the effectiveness and efficiency of the proposed algorithm.
1,786 citations
TL;DR: A novel approach for speckle reduction and coherence enhancement of ultrasound images based on nonlinear coherent diffusion (NCD) model that maximally low-pass filters those parts of the image that correspond to fully developed Speckle, while substantially preserving information associated with resolved-object structures.
Abstract: This paper presents a novel approach for speckle reduction and coherence enhancement of ultrasound images based on nonlinear coherent diffusion (NCD) model. The proposed NCD model combines three different models. According to speckle extent and image anisotropy, the NCD model changes progressively from isotropic diffusion through anisotropic coherent diffusion to, finally, mean curvature motion. This structure maximally low-pass filters those parts of the image that correspond to fully developed speckle, while substantially preserving information associated with resolved-object structures. The proposed implementation algorithm utilizes an efficient discretization scheme that allows for real-time implementation on commercial systems. The theory and implementation of the new technique are presented and verified using phantom and clinical ultrasound images. In addition, the results from previous techniques are compared with the new method to demonstrate its performance.
422 citations
TL;DR: In countries of the Near East region, brucellosis was reported in almost all domestic animals, particularly cattle, sheep and goats, and Brucella melitensis biovar 3 is the most commonly isolated species from animals in Egypt, Jordan, Israel, Tunisia and Turkey.
416 citations
TL;DR: It is concluded that the fixed GnRH antagonist protocol is a short and simple protocol with good clinical outcome, but the lower pregnancy rate compared with the GnRH agonist long protocol and the non-significant difference between both protocols regarding prevention of premature LH surge and prevention of severe ovarian hyperstimulation syndrome necessitates counselling subfertile couples before recommending change from Gn RH agonist to antagonist.
Abstract: Background In the present systematic review, we wished to compare the efficacy of gonadotrophin-releasing hormone (GnRH) antagonist and GnRH agonist administration for controlled ovarian hyperstimulation in assisted conception. Methods Five randomized controlled trials fulfilled the inclusion criteria. In four studies, the multiple low-dose (0.25 mg) antagonist regimen was applied and, in one study, the single high-dose (3 mg) antagonist regimen was investigated. In all trials, reference treatment included a long protocol of GnRH agonist (buserelin, leuprorelin or triptorelin) starting in the mid-luteal phase of the preceding cycle. Results In comparison with the long protocol of GnRH agonist, the overall odds ratio for the prevention of premature LH surges was 1.76 [95% confidence interval (CI) 0.75-4.16], which was not statistically significant. There were significantly fewer clinical pregnancies in those treated with GnRH antagonists (OR 0.79; 95% CI 0.63-0.99). There was no statistically significant reduction in incidence of severe ovarian hyperstimulation syndrome between the two regimens (relative risk 0.51; OR 0.79; 95% CI 0.22-1.18). Conclusions We concluded that the fixed GnRH antagonist protocol is a short and simple protocol with good clinical outcome, but the lower pregnancy rate compared with the GnRH agonist long protocol and the non-significant difference between both protocols regarding prevention of premature LH surge and prevention of severe ovarian hyperstimulation syndrome necessitates counselling subfertile couples before recommending change from GnRH agonist to antagonist. The clinical outcome may be further improved by developing more flexible antagonist regimens, taking into account individual patient characteristics.
335 citations
TL;DR: The results suggest that Nigella sativa oil may play a role against the alterations caused by S. mansoni infection, an effect which may be induced partly by improving the immunological host system and to some extent with its antioxidant effect.
330 citations
TL;DR: In this article, powdery peanuts were treated by one-step procedures to get activated carbon using chemical activation by H3PO4, ZnCl2, KOH and thermal activation by steam pyrolysis.
263 citations
TL;DR: The correlation dimension and largest Lyapunov exponent are used to model the chaotic nature of five different classes of ECG signals and it is indicated that they differ significantly between normal heart rhythm and the different arrhythmia types and, hence, can be rather useful in ECG arrhythmmia detection.
Abstract: We present a study of the nonlinear dynamics of electrocardiogram (ECG) signals for arrhythmia characterization. The correlation dimension and largest Lyapunov exponent are used to model the chaotic nature of five different classes of ECG signals. The model parameters are evaluated for a large number of real ECG signals within each class and the results are reported. The presented algorithms allow automatic calculation of the features. The statistical analysis of the calculated features indicates that they differ significantly between normal heart rhythm and the different arrhythmia types and, hence, can be rather useful in ECG arrhythmia detection. On the other hand, the results indicate that the discrimination between different arrhythmia types is difficult using such features. The results of this work are supported by statistical analysis that provides a clear outline for the potential uses and limitations of these features.
260 citations
TL;DR: A podiform chromitite of the northern Oman ophiolite has been reported to contain 1.5 ppm of total PGE, being highly enriched in the IPGE subgroup and strongly depleted in the PPGE subgroup (Rh, Pt and Pd) as mentioned in this paper.
Abstract: Unusually high, platinum-group element (PGE) enrichments are reported for the first time in a podiform chromitite of the northern Oman ophiolite. The chromitite contains ≤1.5 ppm of total PGE, being highly enriched in the IPGE subgroup (Ir, Os and Ru) and strongly depleted in the PPGE subgroup (Rh, Pt and Pd). Its platinum-group minerals (PGMs) are classified into three types arranged in order of abundance: (1) sulphides (Os-rich laurite, laurite–erlishmanite solid solution and an unnamed Ir sulphide), (2) alloys (Os–Ir alloy and Ir–Rh alloy), and (3) sulpharsenides (irarsite and hollingworthite). The high PGE concentrations are observed only in a discordant chromitite deep in the mantle section, which has high-Cr# (>0.7) spinel with an olivine matrix. All the other types of chromitite (in the Moho transition zone (MTZ) and concordant pods in the deeper mantle section) are poor in PGEs and tend to have spinels with lower Cr# (up to 0.6). This diversity of chromitite types suggests two stages of magmatic activity were responsible for the chromitite genesis, in response to a switch of tectonic setting. The first is residual from lower degree, partial melting of peridotite, which produced low-Cr#, PGE-poor chromitites at the Moho transition zone and, to a lesser extent, within the mantle, possibly beneath a fast-spreading mid-ocean ridge. The second chromitite-forming event involves higher degree partial melting, which produced high-Cr#, PGE-rich discordant chromitite in the upper mantle, possibly in a supra-subduction zone setting.
226 citations
TL;DR: In this article, a comparison of ball milling with single-particle comminution was made, either in terms of the energy to produce new surface or of some size distribution parameter.
215 citations
TL;DR: It is shown that the signature representation can be used to recover scaling transformation as well as matching objects in 3D scenes in the presence of clutter and occlusion.
Abstract: This paper introduces anew free-form surface representation scheme for the purpose of fast and accurate registration and matching. Accurate registration of surfaces is a common task in computer vision. The proposed representation scheme captures the surface curvature information (seen from certain points) and produces images, called "surface signatures," at these points. Matching signatures of different surfaces enables the recovery of the transformation parameters between these surfaces. We propose using template matching to compare the signature images. To enable partial matching, another criterion, the overlap ratio is used. This representation scheme can be used as a global representation of the surface as well as a local one and performs near real-time registration. We show that the signature representation can be used to recover scaling transformation as well as matching objects in 3D scenes in the presence of clutter and occlusion. Applications presented include: free-form object matching, multimodal medical volumes registration, and dental teeth reconstruction from intraoral images.
195 citations
TL;DR: CUR was found to protect rat forebrain against I/R insult and may be attributed to its antioxidant properties and/or its inhibitory effects on xanthine dehydrogenase/xanthine oxidase (XD/XO) conversion and resultant O(2)*(-) production.
TL;DR: In this article, a copper matrix reinforced with either Ni-coated or uncoated SiC and Al 2 O 3 particulate composites was made by means of the powder metallurgy route.
TL;DR: The purpose of the present study was to quantify the effect of iron deficiency anaemia on the levels of HbA2, HbF, and HBA1C, and to suggest that iron deficiency must be corrected before making any diagnostic or therapeutic decisions based on Hb a1C levels.
Abstract: The purpose of the present study was to quantify the effect of iron deficiency anaemia on the levels of HbA2, HbF, and HbA1C. Complete blood counts (CBC) were performed on 730 university students. Serum ferritin, HbA2, HbF, and HbA1C levels were determined for all microcytic/hypochromic subjects. It was found that 81 (11.1%) of the students were microcytic/hypochromic, of which 47 (58.1%) were found to be iron deficient. Twenty-six (32.1%) were beta-thalassemia carriers, 4 (4.9%) were beta-thalassemia carriers with iron deficiency and 4 (4.9%) remained undiagnosed. All the anaemic students were treated with oral iron and followed for 20 weeks. The mean HbA2 level rose significantly (from 1.89% +/- 0.45 to 2.19% +/- 0.53, P 0.05). HbA1C fell significantly after iron treatment, from a mean of 6.15% +/- 0.62 to 5.25% +/- 0.45 (P < 0.001). In conclusion, iron deficiency must be corrected before making any diagnostic or therapeutic decisions based on HbA2 and HbA1C levels.
TL;DR: Comparing the data with that obtained in several Caucasian, African-American and Asian populations, it is found that Egyptians resemble Caucasians with regard to allelic frequencies of the tested variants of CYP 2C9, CYP2C19, CyP2E1 and DPYD.
Abstract: Aims
The goal of this study was to determine the frequencies of important allelic variants of CYP2C9, CYP2C19, CYP2E1 and DPYD in the Egyptian population and compare them with the frequencies in other ethnic populations.
TL;DR: It is shown that the adenovirus was well tolerated, but did not seem to offer significant tumor control in patients treated with dl1520, and it appears that more effective vectors are needed to achieve a useful clinical impact.
Abstract: Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. The prognosis of HCC is poor and current therapies are largely ineffective. Genetic abnormalities are commonly seen in HCC tumors particularly with inactivation of the p53 tumor suppressor. Gene therapy with E1B-deleted (dl1520) adenovirus could be of therapeutic value as it offers the potential of tumor growth control in patients with p53 mutation. Ten patients with posthepatitis cirrhosis and histologically proven HCC were enrolled into an open label, randomized prospective study. Randomization was to receive either percutaneous ethanol injection (control group) or dl1520. Toxicity and complications in the ethanol group were pain and fever, whereas in the gene therapy group complications were minimal. Grade I-II toxicity fever, stable performance status, and no significant rise in liver enzymes were observed in patients treated with dl1520. Analysis of patients' response to treatment in the gene therapy group showed one patient with a partial response and four patients with progressive disease. In the ethanol-treated group two patients had stable disease and three patients showed disease progression. In conclusion, this study showed that the adenovirus was well tolerated, but did not seem to offer significant tumor control. Although only a small number of patients were treated here it appears that more effective vectors are needed to achieve a useful clinical impact.
TL;DR: Tanh method is used to find travelling wave solutions for a single nonlinear reaction-diffusion equation as discussed by the authors, and the extension of the tanh method (a simple transformation) is used for finding travelling wave solution for coupled non-linear reaction diffusion equations.
Abstract: Tanh method is used to find travelling wave solutions for a single nonlinear reaction–diffusion equation. Moreover the extension of the tanh method (a simple transformation) is used to find travelling wave solutions for coupled nonlinear reaction–diffusion equations.
TL;DR: There are desirable, antigen-specific immune responses that would be valuable in a vaccine but they also indicate that there are responses that must be avoided.
TL;DR: In this paper, the authors describe the development of simple approaches in estimating the deflection of FRP reinforced concrete members subjected to flexural stresses and compare the predictions of these approaches with the experimental results obtained by testing seven prototype concrete beams reinforced with glass fibre reinforced polymer, GFRP, and carbon fiber reinforced polymer (CFRP), bars.
TL;DR: In this article, a Q-switched Nd:YAG laser at wavelengths 1064, 532 and 355 nm with maximum energies of 500, 100 and 60 mJ, respectively, and pulse duration of 7 ns with repetition rate of 1 Hz was used.
TL;DR: The rheological behavior and the apparent viscosity values for different gel bases were measured before and after storage under freezing conditions at −4 °C and taken as measures for stability of network structure and the antifungal activity of fluconazole showed the widest zone of inhibition with gel microemulsion.
Abstract: The influence of the vehicle on the release and permeation of fluconazole, a topical antifungal drug dissolved in Jojoba oil was evaluated. Series of Cutina lipogels (Cutina CPA [cetyl palmitate], CBS [mixture of glyceryl stearate, cetearyl alcohol, cetyl palmitate, and cocoglycerides], MD [glyceryl stearate], and GMS [glyceryl monostearate]) in different concentrations as well as gel microemulsion were prepared. In-vitro drug release in Sorensens citrate buffer (pH 5.5) and permeation through the excised skin of hairless mice, using a modified Franz diffusion cell, were performed. The rheological behavior and the apparent viscosity values for different gel bases were measured before and after storage under freezing conditions at −4 °C and were taken as measures for stability of network structure.Candida albicans was used as a model fungus to evaluate the antifungal activity of the best formula achieved. The results of in vitro drug release and its percutaneous absorption showed that the highest values from gel microemulsion were assured. The rheological behavior of the prepared systems showed pseudoplastic (shear-thinning) flow indicating structural breakdown of the existing intermolecular interactions between polymeric chains. Moreover, the stability study revealed no significant difference between viscosity before and after storage for different formulae except for CPA Cutina lipogel (using analysis of variance [ANOVA] test at level of significance .05). The antifungal activity of fluconazole showed the widest zone of inhibition with gel microemulsion. The gel microemulsion is an excellent vehicle for fluconazole topical drug delivery.
TL;DR: In this article, a wide spectral range time resolved laser-induced breakdown spectroscopy has been investigated to evaluate its potential for simultaneous determination of major, minor and trace concentrations in water.
TL;DR: Phacoemulsification with IOL implantation in selected uveitic eyes was safe and effective and acrylic IOLs provided a better visual outcome and lower complication rate than I OLs of other materials.
Abstract: Purpose To evaluate the postoperative outcomes in uveitic eyes after phacoemulsification and posterior chamber intraocular lens (IOL) implantation. Setting Multicenter (19) international study. Methods This prospective randomized comparative interventional case series comprised 140 eyes of 140 patients who had phacoemulsification and implantation of IOLs of various materials: hydrophobic acrylic (n = 48), silicone (n = 44), poly(methyl methacrylate) (PMMA) (n = 26), or heparin-surface-modified PMMA (HSM PMMA) (n = 22). Preoperative and postoperative grading and control of intraocular inflammation were performed. Clinically significant observations, visual outcomes, and the incidence of postoperative complications were recorded. Results At the final follow-up, 64 eyes (46.3%) had a best corrected visual acuity of 20/40 or better, an improvement that was highly significant (P Conclusions Phacoemulsification with IOL implantation in selected uveitic eyes was safe and effective. Acrylic IOLs provided a better visual outcome and lower complication rate than IOLs of other materials.
TL;DR: Metwally and Atiya as mentioned in this paper presented a technique for Monte Carlo simulation of a jump-diffusion process, and illustrate it in pricing path-dependent barrier options by connecting the jumps first, then connecting them with diffusion paths that follow Brownian Bridge processes.
Abstract: Monte Carlo simulation has become a workhorse for practical derivatives valuation, because of its enormous flexibility. It can handle path-dependent payoffs and a wide range of stochastic processes, for example, but the drawback is the computational burden that can become enormous for realistic models of many real-world instruments. In this article, Metwally and Atiya present a clever technique for Monte Carlo simulation of a jump-diffusion process, and illustrate it in pricing path-dependent barrier options. The trick is to simulate the jumps first, then connect them with diffusion paths that follow Brownian Bridge processes. The result is unbiased, accurate, and highly efficient. A further simplification of the procedure that allows a small bias is found to perform even better in terms of accuracy per unit of computation time.
TL;DR: In this article, the formation of singly and doubly deuterated isotopomers of formaldehyde and singly, doubly, and multiply deuteration of methanol on interstellar grain surfaces has been studied with a semi-empirical modified rate approach and a Monte Carlo method in the temperature range 10-20 K.
TL;DR: It is suggested that lymphocytes are more promising than fibroblasts to predict patient's normal tissue response after radiotherapy, and there was a significant difference in chromosomal damage measured in lymphocytes.
TL;DR: This study investigates the possibility of recovering nickel from the spent catalyst (NiO/Al2O3) resulting from the steam reforming process to produce water gas (H2/H2O) in many industries.
TL;DR: The aim of the present work was to improve the therapeutic efficacy of NF via incorporation into different types of carriers, and to investigate their in vitro dissolution and bioavailability in rabbits.
Abstract: Nifedipine (NF) is a poorly water-soluble drug, of low and irregular bioavailability after oral administration. Although some reports have attempted to improve the dissolution of NF using solid dispersions and solubilizers, little literature information is available on the in vivo performance of such preparations. The aim of the present work was to improve the therapeutic efficacy of NF via incorporation into different types of carriers, and to investigate their in vitro dissolution and bioavailability in rabbits. Nifedipine solid dispersions were prepared by fusion, solvent, and freeze-drying methods with polyethylene glycol (PEG) 6000 and PEG monomethylether 5000 (PEG MME 5000). Complexation of NF with beta-cyclodextrin (beta-CyD) and solubilization by sodium lauryl sulfate (SLS) have also been studied. The dissolution was determined by the flow-through cell in order to maintain perfect sink conditions. The solid dispersions resulted in a significant increase in the dissolution rate as compare to pure drug. The highest NF dissolution rate was obtained from solid dispersions containing 95% PEG 6000 prepared by the solvent method. While, unexpectedly, the highest absorption in rabbits was obtained from 95% PEG 6000 prepared by the fusion method. Compared to SLS, beta-CyD gave higher in vitro and in vivo values. Differential scanning calorimetry (DSC) and powder x-ray diffractometry indicated that NF in solid dispersions is homogeneously distributed, and no drug crystallized out of the system. The DSC thermograms of NF-beta-CyD complex and NF/SLS solid mixture showed a decrease in the NF endothermic peak. The x-rays showed different diffraction patterns of pure NF and pure carrier, suggesting the formation of a new solid form.
TL;DR: In this article, reinforced EPDM and nitrile-butadiene rubber (NBR) composites were combined with different concentrations of azodicarbonamide (ADC/K) foaming agent.
Abstract: Reinforced ethylene–propylene–diene terpolymer (EPDM) and nitrile–butadiene rubber (NBR) blends were compounded with different concentrations of azodicarbonamide (ADC/K) foaming agent to obtain foamed EPDM and NBR composites. The mechanical properties under compression and under extension at different temperatures were measured for these foams. It was found that the increase of foaming agent concentration and temperature affect all the mechanical parameters. The obtained stress–strain data are discussed in the light of the continuum mechanics theory for compressible materials.
© 2002 Society of Chemical Industry
TL;DR: In this paper, an extensive overview of the soliton solutions for some famous partial differential equations like KdV, mKdV and Sine-Gordon is given, and relations between the solitus solution and fluid mechanics are shown.
Abstract: This review paper gives an extensive overview of the soliton solutions for some famous partial differential equations like KdV, mKdV, Sine–Gordon, and nonlinear Schrodinger equations. Different analytical methods of treatment as well as those of numerical methods are presented in this review paper. Finally relations between the soliton solution and fluid mechanics are shown.
TL;DR: Tumour cell repopulation seems to be an important determinant of postoperative radiotherapy of locally advanced head and neck cancer despite lack of a definite association between Tpot and treatment outcome.
Abstract: Based on the assumption that an accelerated proliferation process prevails in tumour cell residues after surgery, the possibility that treatment acceleration would offer a therapeutic advantage in postoperative radiotherapy of locally advanced head and neck cancer was investigated. The value of T(pot) in predicting the treatment outcome and in selecting patients for accelerated fractionation was tested. Seventy patients with (T2/N1-N2) or (T3-4/any N) squamous cell carcinoma of the oral cavity, larynx and hypopharynx who underwent radical surgery, were randomized to either (a) accelerated hyperfractionation: 46.2 Gy per 12 days, 1.4 Gy per fraction, three fractions per day with 6 h interfraction interval, treating 6 days per week or (b) Conventional fractionation: 60 Gy per 6 weeks, 2 Gy per fraction, treating 5 days per week. The 3-year locoregional control rate was significantly better in the accelerated hyperfractionation (88 +/- 4%) than in the CF (57+/- 9%) group, P=0.01 (and this was confirmed by multivariate analysis), but the difference in survival (60 +/- 10% vs 46 +/- 9%) was not significant (P=0.29). The favourable influence of a short treatment time was further substantiated by demonstrating the importance of the gap between surgery and radiotherapy and the overall treatment time between surgery and end of radiotherapy. Early mucositis progressed more rapidly and was more severe in the accelerated hyperfractionation group; reflecting a faster rate of dose accumulation. Xerostomia was experienced by all patients with a tendency to be more severe after accelerated hyperfractionation. Fibrosis and oedema also tended to be more frequent after accelerated hyperfractionation and probably represent consequential reactions. T(pot) showed a correlation with disease-free survival in a univariate analysis but did not prove to be an independent factor. Moreover, the use of the minimum and corrected P-values did not identify a significant cut-off. Compared to conventional fractionation, accelerated hyperfractionation did not seem to offer a survival advantage in fast tumours though a better local control rate was noted. This limits the use of T(pot) as a guide for selecting patients for accelerated hyperfractionation. For slowly growing tumours, tumour control and survival probabilities were not significantly different in the conventional fractionation and accelerated hyperfractionation groups. A rapid tumour growth was associated with a higher risk of distant metastases (P=0.01). In conclusion, tumour cell repopulation seems to be an important determinant of postoperative radiotherapy of locally advanced head and neck cancer despite lack of a definite association between T(pot) and treatment outcome. In fast growing tumours accelerated hyperfractionation provided an improved local control but without a survival advantage. To gain a full benefit from treatment acceleration, the surgery-radiotherapy gap and the overall treatment time should not exceed 6 and 10 weeks respectively.