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result(s) for
"Hamdy, Ziad A."
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Biosynthesis of trimetallic nanoparticles and their biological applications: a recent review
by
Nahool, Ahmed Abdelhay
,
Dora, Mohamed Soliman
,
Saied, Ebrahim
in
Bacteria - metabolism
,
Biochemistry
,
Biological properties
2025
Trimetallic nanoparticles (TMNPs) have emerged as a pivotal area of research due to their unique properties and diverse applications across medicine, agriculture, and environmental sciences. This review provides several novel contributions that distinguish it from existing literature on trimetallic nanoparticles (TMNPs). Firstly, it offers a focused exploration of TMNPs, specifically addressing their unique properties and applications, which have been less examined compared to other multimetallic nanoparticles. This targeted analysis fills a significant gap in current research. Secondly, the review emphasizes innovative biosynthesis methods utilizing microorganisms and plant extracts, positioning these green synthesis approaches as environmentally friendly alternatives to traditional chemical methods. This focus aligns with the increasing demand for sustainable practices in nanotechnology. Furthermore, the review integrates discussions on both medical and agricultural applications of TMNPs, highlighting their multifunctional potential across diverse fields. This comprehensive perspective enhances our understanding of how TMNPs can address various challenges. Additionally, the review explores the synergistic effects among the different metals in TMNPs, providing insights into how these interactions can be harnessed to optimize their properties for specific applications. Such discussions are often overlooked in existing studies. Moreover, this review identifies critical research gaps and challenges within the field, outlining future directions that encourage further investigation and innovation in TMNP development. By doing so, it proactively contributes to advancing the field. Finally, the review advocates for interdisciplinary collaboration among material scientists, biologists, and environmental scientists, emphasizing the importance of diverse expertise in enhancing the research and application of TMNPs.
Journal Article
Evaluation of the Impact of High Penetration Levels of PV Power Plants on the Capacity, Frequency and Voltage Stability of Egypt’s Unified Grid
by
Kuznetsov, Oleg N.
,
Diab, Ahmed A. Zaki
,
Ali, Ziad M.
in
Alternative energy sources
,
Egypt’s national grid
,
Electricity
2019
In this paper, the impact of integrating photovoltaic plants (PVPs) with high penetration levels into the national utility grid of Egypt is demonstrated. Load flow analysis is used to examine the grid capacity in the case of integrating the desired PVPs and computer simulations are also used to assess the upgrading of the transmission network to increase its capacity. Furthermore, the impact of increasing the output power generated from PVPs, during normal conditions, on the static voltage stability was explored. During transient conditions of operation (three-phase short circuit and outage of a large generating station), the impact of high penetration levels of PVPs on the voltage and frequency stability has been presented. Professional DIgSILENT PowerFactory simulation package was used for implementation of all simulation studies. The results of frequency stability analysis proved that the national grid could be maintained stable even when the PVPs reached a penetration level up to 3000 MW of the total generation in Egypt. Transmission network upgrading to accommodate up to 3000 MW from the proposed PV power plants by 2025 is suggested. In addition, analysis of voltage stability manifests that the dynamic behavior of the voltage depends remarkably on the short circuit capacity of the grid at the point of integrating the PVPs.
Journal Article
Optimal Design and Control of MMC STATCOM for Improving Power Quality Indicators
by
Ahmed A. Zaki Diab
,
Terad Ebraheem
,
Hamdy M. Sultan
in
Atom search optimization
,
Biology (General)
,
Bridges
2020
In recent years, modular multilevel converters (MMC) are becoming popular in the distribution and transmission of electrical systems. The multilevel converter suffers from circulating current within the converter that increases the conduction loss of switches and increases the thermal stress on the capacitors and switches’ IGBTs. One of the main solutions to control the circulating current is to keep the capacitor voltage balanced in the MMC. In this paper, a new hybrid control algorithm for the cascaded modular multilevel converter is presented. The Harris hawk’s optimization (HHO) and Atom search optimization (ASO) are used to optimally design the controller of the hybrid MMC. The proposed structure of modular multilevel inverters allows effective operation, a low level of harmonic distortion in the absence of output voltage filters, a low switching frequency, and excellent flexibility to achieve the requirements of any voltage level. The effectiveness of the proposed controller and the multilevel converter has been verified through testing with the application of the MMC-static synchronous compensator (STATCOM). The stability of the voltage capacitors was monitored with balanced and unbalanced loads on the studied network.
Journal Article
Attractive study of the antimicrobial, antiviral, and cytotoxic activity of novel synthesized silver chromite nanocomposites
2022
Antibiotic resistance is a global problem. This is the reason why scientists search for alternative treatments. In this regard, seven novel silver chromite nanocomposites were synthesized and assayed to evaluate their antimicrobial, antiviral, and cytotoxic activity. Five bacterial species were used in this study: three Gram-positive (Bacillus subtilis, Micrococcus luteus, and Staphylococcus aureus) and two Gram-negative (Escherichia coli and Salmonella enterica). Three fungal species were also tested: Candida albicans, Aspergillus niger, and A. flavus. The MIC of the tested compounds was determined using the bifold serial dilution method. The tested compounds showed good antibacterial activity. Maximum antibacterial activity was attained in the case of 15 N [Cobalt Ferrite (0.3 CoFe2O4) + Silver chromite (0.7 Ag0.5Cr2.5O4)] against M. luteus. Concerning antifungal activity, C. albicans was the most susceptible fungal species. The maximum inhibition was recorded also in case of 15 N [Cobalt Ferrite (0.3 CoFe2O4) + Silver chromite (0.7 Ag0.5Cr2.5O4)]. The most promising antimicrobial compound 15 N [Cobalt Ferrite (0.3 CoFe2O4) + Silver chromite (0.7 Ag0.5Cr2.5O4)] was assayed for its antiviral and cytotoxic activity. The tested compound showed weak antiviral activity. The cytotoxic activity against Mammalian cells from African Green Monkey Kidney (Vero) cells was detected. The inhibitory effect against Hepatocellular carcinoma cells was detected using a MTT assay. The antimicrobial effect of the tested compounds depends on the tested microbial species. The tested compounds could be attractive and alternative antibacterial compounds that open a new path in chemotherapy.
Journal Article
Knowledge, attitudes, practices and perceived barriers towards research in undergraduate medical students of six Arab countries
by
Ragab, Khaled Mohamed
,
Assar, Ahmed
,
Badr, Helmy
in
Arabs
,
Attitudes
,
Beliefs, opinions and attitudes
2022
Background
The involvement of the undergraduates in the research field requires a better view of their potential and the anticipated barriers facing them. This study aims to assess the undergraduates' knowledge, attitudes, practices and perceived barriers towards research in six Arab countries.
Methods
A cross sectional study included medical students from six Arab countries, where a self-administered five-section questionnaire was used to assess the students' demographics, knowledge, attitudes, practices and perceived barriers. The questionnaire was distributed in the online educational platforms of the participating medical schools in the six included countries.
Results
The total sample of recruited students was 2989, the majority of students (91.6%) showed poor level of knowledge regarding research. Generally high levels of positive attitudes towards research, research relevance and usefulness were found, with moderate levels of perception of research anxiety and difficulty. 33.7% (
n
= 1006) participated in an actual research project before with a mean of .5 publications per student. Cross-sectional studies were the most common type of studies conducted by students (38.6%), followed by case reports (23.9%). Lack of access to lab equipment for lab research (68.1%), the priority of education over research (66.8%), and lack of time because of educational tasks (66.1%) were generally the top perceived barriers towards research practice.
Conclusion
In the current study, the participants showed a poor knowledge level with associated positive attitudes towards research. One third of the students participated in research projects that mostly were cross-sectional studies and case reports. Educational tasks and lack of support were the most prevalent barriers. The students' positive attitudes towards research need to be translated into better knowledge and appropriate practice, which can be done by development of better training systems and more structured mentoring.
Journal Article
Design and Modeling of a Robust Sensorless Control System for a Linear Permanent Magnet Synchronous Motor
by
Ahmed, Mahrous
,
Al-Gahtani, Saad F.
,
Echeikh, Hamdi
in
Control systems design
,
Controllers
,
Design
2021
The paper is concerned with designing an effective controller for a linear tubular homopolar (LT-H) motor type. The construction and operation of the LT-H motor are first described in detail. Then, the motor model is represented in the direct-quadrature (d-q) axes in order to facilitate the design of the control loops. The designed control system consists of two main loops: the current control loop and velocity adaptation loop. The determination of the regulator’s gains is accomplished through deriving and analyzing the transfer functions of the loops. To enhance the system’s robustness, a robust variable estimator is designed to observe the velocity and stator resistance. Different performance evaluation tests are performed using MATLAB/Simulink software to validate the controller’s robustness for variable-speed operation and load force changes as well. The obtained results reveal the appropriate dynamics of the motor thanks to the well-designed control system.
Journal Article
Competing endogenous RNA network: Potential entrants to gene editing in Hepatocellular Carcinoma Gene editing of ceRNA in Hepatocellular Carcinoma
2018
Hepatocellular Carcinoma (HCC) is the leading cause of cancer deaths worldwide as well as in Egypt. We aimed to use Clustered Regulatory Interspaced Short Palindromic Repeats (CRISPR) gene editing technique to induce forced down-regulation of the circRNA which consequently modified miRNA expression in HepG2 cell line to prove the regulatory relationship between the RNA parts of an in silico-detected competing endogenous RNA network in HCC
We first retrieved hsa_circ_0000064-miR-1285-TRIM2 mRNA from public microarray databases followed by in silico modelling to mimic the regulation kinetics of cirRNA associated ceRNA network. Secondly, we performed polymerase chain reaction (PCR)-based amplification of synthetic fragments, Gibson assembly of both CRISPR and non CRISPR based circuits, E-coli transformation, plasmid purification, HePG2 cell line transfection. Finally Expression levels of the chosen RNAs in hepatocellular carcinoma (HCC) cell line, HepG2, were examined by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and the cytotoxic effect was validated by viability assay.TRIM2 protein expression was proved by immunohistochemistry and flowcytometry.
Induction of hsa_circ_0000064 into HepG2 cell line via CRISPR-and non-CRISPR mediated synthetic circuit resulted in statistically significant decrease in cell number and, then, cellular viability with marked increase in hsa_circ_0000064 and TRIM2 mRNA levels and concomitant decrease in miR-1285 expression in HepG2 cell line compared with control (p<0.0). Moreover exogenous expression of hsa_circ_0000064 in HepG2 cell line showed increased expression of the tumor suppressor protein, TRIM2.
Our integrative approach, including in silico data analysis and experimental validation proved that CRISPR-mediated synthetic circuit-based overexpression of hsa_circ_0000064 was more efficient than conventional transient transfection, representing a promising therapeutic strategy for HCC.
Our Data was made available online on the IGEM wiki of team AFCM-EGYPT: http://2017.igem.org/Team:AFCM-Egypt. Synthetic parts have been submitted to IGEM Parts Registry.
The project was funded by Armed Forces College of Medicine AFCM, Zewail City of Science and Technology, National Research Center NRC, VitaBiotics, PHARCO Pharmaceuticals, Sim Era and DANUB Paintings. IDT provided 20 kb of DNA synthesis. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing endogenous RNA network: Potential entrants to gene editing in Hepatocellular Carcinoma
2018
Background: Hepatocellular Carcinoma (HCC) is the leading cause of cancer deaths worldwide as well as in Egypt. We aimed to use Clustered Regulatory Interspaced Short Palindromic Repeats (CRISPR) gene editing technique to induce forced down-regulation of the circRNA which consequently modified miRNA expression in HepG2 cell line to prove the regulatory relationship between the RNA parts of an in silico-detected competing endogenous RNA network in HCC. Method: We first retrieved hsa_circ_0000064-miR-1285-TRIM2 mRNA from public microarray databases followed by in silico modelling to mimic the regulation kinetics of cirRNA associated ceRNA network .Secondly, we performed polymerase chain reaction (PCR)-based amplification of synthetic fragments, Gibson assembly of both CRISPR and non CRISPR based circuits, E-coli transformation, plasmid purification, HePG2 cell line transfection. Finally Expression levels of the chosen RNAs in hepatocellular carcinoma (HCC) cell line, HepG2, were examined by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and the cytotoxic effect was validated by viability assay.TRIM2 protein expression was proved by immunohistochemistry and flowcytometry. Results: Induction of hsa_circ_0000064 into HepG2 cell line via CRISPR- and non-CRISPR mediated synthetic circuit resulted in statistically significant decrease in cell number and, then, cellular viability with marked increase in hsa_circ_0000064 and TRIM2 mRNA levels and concomitant decrease in miR-1285 expression in HepG2 cell line compared with control (p<0.0).Moreover exogenous expression of hsa_circ_0000064 in HepG2 cell line showed increased expression of the tumor suppressor protein, TRIM2. Conclusions: Our integrative approach, including in silico data analysis and experimental validation proved that CRISPR-mediated synthetic circuit-based overexpression of hsa_circ_0000064 was more efficient than conventional transient transfection, representing a promising therapeutic strategy for HCC.