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252
result(s) for
"Sayed, Emad"
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Thermal radiation effects on nanofluid flow over a vertical cone in the presence of pressure work
2025
This study examines the effect of thermal radiation on nanofluid flow and heat transfer over a truncated cone in the presence of pressure work, a problem critical for thermal management and industrial cooling systems. Using similarity transformations, the governing equations are converted into coupled nonlinear partial differential equations and solved numerically via the Legendre collocation method. It gives a high degree of consistency between the proposed numerical solutions and the results previously reported under specific cases. The Prandtl number, pressure work parameter, radiation parameter, and nanoparticle volume fraction all have a major impact on flow and thermal behavior, according to the main results. Nanofluids enhance the transfer of heat by 10–40% when compared to pure fluid, cooling speeds up, and surface strength and hardness improve. Also, the kinds of nanofluid and the parameters related to the volume percentage of nanoparticles are crucial in determining the flow behavior. The surface mechanical properties are advanced by using 10% nanoparticle nanofluid rather than 5%. It has been discovered that the strength and hardness of the surface will enhance with an increase in the pressure work parameter when employing Cu-water nanofluid, but they will decrease with an increase in the thermal radiation parameter values. The novelty of this work lies in the application of the Legendre collocation method to this problem, along with new quantitative insights into how pressure work and radiation interact with nanofluids, providing practical guidelines for optimizing thermal and mechanical performance in industrial systems.
Journal Article
A dual enhanced stochastic gradient descent method with dynamic momentum and step size adaptation for improved optimization performance
by
Mokhtar, Mohamed A.
,
Fathy, Mohamed
,
Dahab, Yasser A.
in
639/705/1041
,
639/705/117
,
Adaptation
2025
In modern machine learning, optimization algorithms are crucial; they steer the training process by skillfully navigating through complex, high-dimensional loss landscapes. Among these, stochastic gradient descent with momentum (SGDM) is widely adopted for its ability to accelerate convergence in shallow regions. However, SGDM struggles in challenging optimization landscapes, where narrow, curved valleys can lead to oscillations and slow progress. This paper introduces dual enhanced SGD (DESGD), which addresses these limitations by dynamically adapting both momentum and step size on the same update rules of SGDM. In two optimization test functions, the Rosenbrock and Sum Square functions, the suggested optimizer typically performs better than SGDM and Adam. For example, it accomplishes comparable errors while achieving up to 81–95% fewer iterations and 66–91% less CPU time than SGDM and 67–78% fewer iterations with 62–70% quicker runtimes than Adam. On the MNIST dataset, the proposed optimizer achieved the highest accuracies and lowest test losses across the majority of batch sizes. Compared to SGDM, they consistently improved accuracy by about 1–2%
,
while performing on par with or slightly better than Adam in accuracy and error. Although SGDM remained the fastest per-step optimizer, our method’s computational cost is aligned with that of other adaptive optimizers like Adam. This marginal increase in per-iteration overhead is decisively justified by the substantial gains in model accuracy and reduction in training loss, demonstrating a favorable cost-to-performance ratio. The results demonstrate that DESGD is a promising practical optimizer to handle scenarios demanding stability in challenging landscapes.
Journal Article
Hall current and joule heating effects on free convection flow of a nanofluid over a vertical cone in presence of thermal radiation
by
Abbas, Wael
,
Sayed, Emad
in
Boundary conditions
,
Computational fluid dynamics
,
Convection heating
2017
The effects of Hall current and Joule heating on flow and heat transfer of a nanofluid along a vertical cone in the presence of thermal radiation is considered. The flow is subjected to a uniform strong transverse magnetic field normal to the cone surface. Similarity transformations are used to convert the non-linear boundary- layer equations for momentum and energy equations to a system of non-linear ordinary differential equations which are then solved numerically with appropriate boundary conditions. The solutions are presented in terms of local skin friction, local Nusselt number, velocity, and temperature profiles for values of magnetic parameter, Hall parameter, Eckert number, radiation parameter, and nanoparticle volume fraction. Comparison of the numerical results made with previously published results under the special cases, the results are found to be in an excellent agreement. It is also found that, nanoparticle volume fraction parameter and types of nanofluid play an important role to significantly determine the flow behavior. nema
Journal Article
Computational study of fractional partial differential equations using the second-kind Chebyshev collocation technique with error analysis
2026
This paper presents and establishes the Chebyshev collocation method, which generates numerical solutions for nonlinear fractional partial differential equations such as the fractional diffusion, wave, and Korteweg–De Vries equations. To obtain the novel fractional derivative operational matrix of the shifted Chebyshev polynomials, new theorems and lemmas have been proved. Caputo’s fractional-order derivative definition is used to represent the fractional-order terms. This approach transforms the problem under discussion into a nonlinear algebraic system of equations that Newton’s method is applied to solve numerically. The error analysis is determined to justify the proposed technique. Several numerical examples are provided to illustrate the accuracy and applicability of the suggested method. The estimated, residual, and absolute errors are computed for each numerical example, and comparisons with other approaches are shown to strengthen the reliability and effectiveness of the suggested method.
Journal Article
Zingerone Attenuates Carfilzomib-Induced Cardiotoxicity in Rats through Oxidative Stress and Inflammatory Cytokine Network
by
Alshahrani, Saeed
,
Algassmi, Sameeh M.
,
Shaheen, Emad Sayed
in
Animals
,
Antioxidants
,
Antioxidants - metabolism
2022
Carfilzomib (CFZ) is an anticancer medication acting as a selective proteasome inhibitor. However, it can cause cardiovascular problems, increasing mortality and morbidity. This study aimed to investigate whether zingerone (ZRN) could help reduce carfilzomib-induced cardiotoxicity in Wistar albino rats. Rats were divided into five groups of six animals each. The first group received normal saline as a control (NC); the second group received multiple doses (six) of CFZ (4 mg/kg) intraperitoneally (IP); the third and fourth groups received zingerone (50 mg/kg and 100 mg/kg oral) along with six doses of CFZ for 16 days; and the fifth group received only 100 mg/kg zingerone orally. Hematological, biochemical, oxidative stress, and histopathological studies confirmed the findings of CFZ-induced cardiotoxicity. We found that ZRN significantly attenuated the effects of CFZ on oxidative stress by enhancing the antioxidant properties of glutathione (GSH), catalase (CAT), and superoxide dismutase (SOD). Additionally, ZRN reduces inflammatory cytokines and apoptotic markers, such as IL-1β, IL-6, TNFα, and caspase-3. Overall, zingerone prevents carfilzomib-induced cardiotoxicity in rats, as evidenced by histopathological studies.
Journal Article
Design and characterization of Lactotransferrin peptide-loaded dextran-docosahexaenoic acid nanoparticles: an immune modulator for hepatic damage
by
Shaheen, Emad Sayed
,
Madkhali, Osama A.
,
Alshammari, Abdulrahman
in
631/154
,
631/250
,
639/925
2023
The primary objective of this research was to create injectable delivery formulations using Lactotransferrin (LTF) peptide-loaded dextran nanoparticles coated with docosahexaenoic acid. These nanoparticles, designated as LLDDNP, underwent a lyophilization process. The study encompassed a comprehensive investigation, including physicochemical characterization, in vivo assessment of biomarkers, and an examination of immune response through cytokine modulation. The zeta potential of LLDDNP was − 24.5 ± 12 mV, while their average particle size was 334.9 z.d.nm. The particles exhibited a conductivity of 2.10 mS/cm, while their mobility in the injectable dosage form was measured at − 3.65 µm cm/Vs. The scanning electron microscopy investigation, the lyophilization processes resulted in discrete particles forming particle aggregations. However, transmission electron microscopy analysis revealed that LLDDNP is spherical and smooth. The thermogram showed that about 95% of LLDDNP's weight was lost at 270 °C, indicating that the particles are extremely thermal stable. The XRD analysis of LLDDNP exhibited clear and distinctive peaks at
2θ
angles, specifically at 9.6°, 20.3°, 21.1°, 22°, 24.6°, 25.2°, 36°, and 44.08°, providing compelling evidence of the crystalline nature of the particles. According to proton NMR studies, the proton dimension fingerprint region of LLDDNP ranges from 1.00 to 1.03 ppm. The in vitro release of LTF from LLDDNP was found to follow zero-order kinetics, with a commendable R
2
value of 0.942, indicating a consistent and predictable release pattern over time. The in vivo investigation revealed a significant impact of hepatotoxicity on the elevation of various cytokines, including IL-1β, IL-6, IL-8R, TNF-α, IL-2, IL-4, IL-10, and IFN-γ. Additionally, the presence of hepatotoxicity led to an increase in apoptosis markers, namely caspase 3 and caspase 9, as well as elevated levels of liver biomarkers such as CRP, ALP, ALT, and AST. In contrast, the treatment with LLDDNP modulated the levels of all biomarkers, including cytokines level in the treatment group extremely high significant at
p
< 0.001.
Journal Article
Determining factors that affect risk disclosure level in Egyptian banks
by
Abdel Azeem Mohamed Khalil, Manal
,
Sayed Abd Elghaffar, Emad
,
Mohamed Abotalib, Ahmed
in
Banks
,
Consumer advertising
,
content analysis
2019
This study aims to measure the risk disclosure level in Egyptian banks and to investigate its determinants. The sample consisted of 28 banks during the period from 2010 to 2017. An unweighted risk disclosure index including six categories was used: credit risk, market risk, liquidity risk, capital structure and adequacy risk, operational risk, and other non-financial risks. Also, a content analysis approach was used to measure the actual level of risk disclosure. The findings demonstrated that there was an average level of total risk disclosure of all sample banks. The results showed that banks with a higher percentage of independent board membership, large board size, large audit committee size, duality, higher institutional ownership, and banks audited by one of big four audit firms were more motivated to increase risk disclosure. Also, the results showed that leverage, bad news, and bank social responsibility have a negative relationship with the level of risk disclosure. Overall, the results indicated that leverage, board size, audit committee size, auditor types, independence, duality, institutional ownership, bank social responsibility, and bad news are the main factors affecting the level of risk disclosure in Egyptian banks. The findings of this paper have a number of important implications. The risk disclosure in the banking sector is important for stakeholders such as investors and depositors. Also, risk disclosure index helps the regulatory bodies to evaluate the risk disclosure practice in Egyptian banks. This paper contributes to analyzing factors affecting banks managers’ decision to disclose risk information in emerging countries such as Egypt.
Journal Article
Cathine and cathinone disposition kinetics and neurotransmitter profile in several organs of rats exposed to a single dose of Catha edulis (Vahl) Forssk. ex Endl. extract
2023
Catha edulis (Vahl) Forssk. ex Endl. (Khat) is a stimulant plant that contains cathine and cathinone, which its abuses induce euphoria, alertness, and motor activity. Since the toxicokinetics of these substances remain unclear, this study was carried out to investigate the disposition kinetics of cathine and cathinone, the neurotransmitter profile, following a single dose of C. edulis extract in rats.Twenty-four adult male Wistar albino rats (250–300 g) were randomly selected and divided into six groups of four rats each. All groups received a single oral dose of 2,000 mg/kg body weight, and blood and tissue samples from the brain, lung, heart, liver, and kidney were obtained at intervals of 0.5, 1, 2.5, 5, 12, and 24 h. The cathine and cathinone concentrations were identified and quantified using ion trap ultra-high performance liquid chromatography (HPLC-IT/MS). The neurotransmitter profile was detected using the quadrupole time of flight UPLC-QTOF/MS method.The lung, liver, and heart tissues attained the highest levels of cathine, while the highest level of cathinone was determined in the heart. Cathine and cathinone concentrations in the blood and heart peaked at 0.5 h. The concentrations peaked in the brain 2.5 h later, indicating that the heart had an immediate effect, whereas the brain had a longer-lasting one. They have longer half-lives (2.68 and 5.07 h, respectively) and may remain in the brain for longer durations (3.31 and 2.31 h, respectively). The neurotransmitters epinephrine, dopamine, norepinephrine, and serotonin were detected in a delayed, prolonged and organ-specific manner.Cathine and cathinone were deposited in considerable concentrations in all tissues analyzed, with the highest Cmax in the lung and Tmax in the heart tissues but not in the brain. In addition, neurotransmitters such as adrenaline, dopamine, norepinephrine, and serotonin were differentially detected in all tested samples in a organ-specific fashion. More study is needed to identify cathine and cathinone’s effects on neurotransmitter profiles. Nevertheless, these findings provided a further basis for experimental, clinical, and forensic investigations.
Journal Article
Cash holding and bankruptcy risk in Egyptian firms: the moderating effect of corporate social responsibility
2025
PurposeThis study aims to investigate the impact of cash holding (CH) on bankruptcy (BR) risk. This study also examines the moderating effect of corporate social responsibility (CSR) practices on this relationship.Design/methodology/approachThe data were extracted from firms' annual reports. The panel data were used for 68 firms listed at the Egyptian Stock Exchange (EGX) with a total of 340 observations from 2015 to 2019. The research hypotheses were tested using the panel corrected standards errors (PCSE) method and the feasible generalized least squares (FGLS) method.FindingsThe results reveal that (1) CH has a positive effect on the Z-score (decreasing bankruptcy risk) of the Egyptian listed firms. (2) Egyptian firms that practice CSR have a low level of bankruptcy risk. (3) CSR practices in Egyptian listed firms support the positive relationship between CH and Z-score (declining bankruptcy risk).Research limitations/implicationsThe limitations of this study include a relatively small sample size. In addition, the analysis doesn't include other measures of bankruptcy risk due to a lack of data.Practical implicationsThe findings of this study will help investors and creditors to evaluate and predict the firms' bankruptcy risk. This study highlights the importance of cash holding for firms in emerging economies. Firms may hold cash to support liquidity, overcome financial distress risk, lower the cost of capital, increase future investment opportunities and reduce uncertainty. Additionally, the results would also help the policymakers, regulators at the EGX and Financial Regulatory Authority and stakeholders to realize the importance of cash holding, evaluate the cash liquidity in Egyptian listed firms, predict the firms' financial distress and consider the consequences of the CSR practices in accordance with Egypt's vision 2030.Originality/valueConsistent with liquidity preference theory and trade-off theory, this study adds evidence to the literature on bankruptcy risk by investigating the effect of cash holding on bankruptcy risk in emerging economies. According to Egypt's vision 2030, the empirical findings in this study extend previous findings by providing strong additional evidence in emerging economies regarding the moderating effect of CSR practices on the association between cash holding and bankruptcy risk. To the best of our knowledge, this study is the first to investigate the relationship between CSR, CH and BR risk in Egypt.
Journal Article
Design, Characterization, and Immune Augmentation of Docosahexaenoic Acid Nanovesicles as a Potential Delivery System for Recombinant HBsAg Protein
by
Shaheen, Emad Sayed
,
Elmobark, Mohamed Eltaib
,
Salawi, Ahmad
in
Aluminum
,
Antibodies
,
Antigens
2022
Recombinant HBsAg-loaded docosahexaenoic acid nanovesicles were successfully developed, lyophilized (LRPDNV) and characterized for their physico-chemical properties. The zetapotential (ZP) of LRPDNV was −60.4 ± 10.4 mV, and its polydispersity (PDI) was 0.201, with a % PDI of 74.8. The particle sizes of LRPDNV were 361.4 ± 48.24 z. d.nm and 298.8 ± 13.4 r.nm. The % mass (r.nm) of LRPDNV in a colloidal injectable system was 50, its mobility value was −3.417 µm cm/Vs, while the conductivity of the particles was 0.728 (mS/cm). Transmission electron microscopic (TEM) analysis showed smooth morphological characteristics of discrete spherical LRPDNV. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) of LRPDNV revealed that LRPDNV is thermostable. The X-ray diffraction (XRD) studies showed a discrete crystalline structure of LRPDNV at 2θ. Nuclear magnet resonance (NMR) studies (1H-NMR and 13C-NMR spectrum showed the discrete structure of LRPDNV. The immunogenicity study was performed by antibody induction technique. The anti-HBs IgG levels were elevated in Wistar rats; the antibody induction was observed more in the product (LRPDNV) treatment group when compared to the standard vaccine group. The level of antibodies on the 14th and 30th day was 6.3 ± 0.78 U/mL and 9.24 ± 1.76 U/mL in the treatment and standard vaccine groups, respectively. Furthermore, the antibody level on the 30th day in the treatment group was 26.66 ± 0.77 U/mL, and in the standard vaccine group, the antibody level was 23.94 ± 1.62 U/mL. The LRPDNV vaccine delivery method released HBsAg sustainably from the 14th to the 30th day. The results of this study indicate the successful formulation of DHA nanovesicles which have great potential as an adjuvant system for the delivery of recombinant HBsAg protein.
Journal Article