Omar Abd-Elkader - Academia.edu (original) (raw)

Papers by Omar Abd-Elkader

Nucleation and Atmospheric Aerosols, 2012

Thin films of Zinc Oxide (ZnO) were deposited on slide glass substrates by the chemical bath depo... more Thin films of Zinc Oxide (ZnO) were deposited on slide glass substrates by the chemical bath deposition technique (CBD). The formation of nanostructured ZnO thin films have been confirmed through XRD, TEM, and SEM. The structure properties were investigated by XRD. The optical properties were measured by UV-VIS spectrophotometer. The absorption coefficient is calculated from recorded data and it is best fitted for direct band gap. The direct band gap was in range 3.8-4.0 eV.

Materials research express, Feb 27, 2017

Nickel/Nickel oxide (Ni/NiO) nanoparticles catalyst is prepared by microwave-assisted liquid-phas... more Nickel/Nickel oxide (Ni/NiO) nanoparticles catalyst is prepared by microwave-assisted liquid-phase deposition using ethylene glycol (EG) and water mixture under atmospheric conditions. The physicochemical characterizations of the catalyst carried out by surface area analyzer, x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), electron microscopes measurements suggest the formation of crystalline nanoparticles structure of NiO. The surface area of Ni/NiO prepared using EG/water mixture reaches 70 m2 g−1 which is 2-fold enhsancement in surface area in comparison with NiO prepared in pure EG and an order of magnitude higher than that of bulk nickel prepared in pure water. The methanol electro-oxidation activity of the Ni/NiO nanoparticles obtained in EG/water mixture displayed more than 4-fold increase in oxidation current at 1.7 V versus RHE in comparison with NiO nanoparticles obtained in EG and 20-fold increase compared to bulk nickel catalyst concord with the enhancement of electro-active surface area. The results show the Ni/NiO nanoparticles produced by microwave assisted synthesis has superior activity for methanol oxidation in alkaline solution over the other nickel based catalysts and has potential for mass production.

Frontiers in Pharmacology, 2020

Alzheimer’s disease (AD) is a progressive cortex and hippocampal neurodegenerative disease which ... more Alzheimer’s disease (AD) is a progressive cortex and hippocampal neurodegenerative disease which ultimately causes cognitively impaired decline in patients. The AD pathogen is a very complex process, including aggregation of Aβ (β-amyloid peptides), phosphorylation of tau-proteins, and chronic inflammation. Exactly, resveratrol, a polyphenol present in red wine, and many plants are indicated to show the neuroprotective effect on mechanisms mostly above. Resveratrol plays an important role in promotion of non-amyloidogenic cleavage of the amyloid precursor protein. It also enhances the clearance of amyloid beta-peptides and reduces the damage of neurons. Most experimental research on AD and resveratrol has been performed in many species, both in vitro and in vivo, during the last few years. Nevertheless, resveratrol’s effects are restricted by its bioavailability in the reservoir. Therefore, scientists have tried to improve its efficiency by using different methods. This review focus...

Journal of Physics and Chemistry of Solids, 2021

Abstract Herein, we present the effect of ethylene glycol (EG) concentration on the size of CdO–N... more Abstract Herein, we present the effect of ethylene glycol (EG) concentration on the size of CdO–NiO–Fe2O3 nanocomposites with the intention to enhance their structural and optical properties for antibacterial activity. The self-combustion method was used to prepare trimetal oxide (TMO) nanocomposites. Structural and morphological properties of the prepared samples were studied using X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. Absorbance and photoluminescence (PL) spectra of TMO nanocomposites were investigated using a UV–visible spectrophotometer and PL spectroscopy. XRD measurements showed that CdO and NiO have a face-centered cubic structure, while Fe2O3 showed pure maghemite (γ-Fe2O3) phase with a cubic spinel crystalline structure. TEM measurements showed that the size of the TMO nanocomposites increased from about 9.4 to 20.8 nm as the EG concentration decreased from 1 M to 0.001 M. FTIR spectra showed the characteristics peaks for CdO, NiO, and γ-Fe2O3. Optical bandgap values of samples showed variation related to EG concentration due to the quantum confinement of TMO nanocomposites. Antibacterial activity of TMO nanocomposites was tested against Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, and Moraxella catarrhalis) and Gram-positive bacteria (Staphylococcus aureus). It is the first time TMO nanocomposites have been tested against M. catarrhalis. The zones of inhibition of TMO nanocomposites were 13, 25, 25, and 25 mm for E. coli, P. aeruginosa, M. catarrhalis, and S. aureus, respectively. The enhanced ZOI of TMO nanocomposites makes them good candidates for antibiotic development.

Agronomy, Jun 26, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Results in Physics

Clean air is essential for a sustainable and healthy human settlement. Hazardous gases produced b... more Clean air is essential for a sustainable and healthy human settlement. Hazardous gases produced by industry ruin the air quality, thus it is crucial to find efficient treatment methods. The capability of ultrathin TiO 2 quantum dots to adsorb different gases, namely CO, CO 2 , SO 2 , H 2 S, NO 2 , NH 3, and O 3 , are investigated using DFT calculations. Based on electronic properties and molecular electrostatic potential, edge Ti-atoms are highly interactive and are suitable active sites for gas adsorption. Adsorption energy, charge transfer, and atom in molecule analysis confirm that all the considered gases are successfully absorbed. The UV-Vis spectrum experience redshift /blueshift after adsorption of (CO, CO 2 , H 2 S, NH 3)/(H 2 S, O 3) and thus can be used to test the adsorption process. These favorable adsorption properties and the calculated quick recovery time make the two-dimensional TiO 2 quantum dots potential candidates for efficient and reusable gas sensors.

Sustainability

The Gulf of Gabès, located on the south-east Tunisian coast, is an important maritime area, with ... more The Gulf of Gabès, located on the south-east Tunisian coast, is an important maritime area, with great influence on the local economy and human welfare. The aim of the current study was to assess the response of meiobenthic copepod populations from this gulf to anthropogenic disturbances. Nine sampling sites, situated along the shores of the gulf were surveyed seasonally from winter of 2004 to autumn of 2005. Interestingly, this biotope has one of the highest semi-diurnal tides in the Mediterranean Sea. Despite the fact that the data being presented here are not that new, such a high maximum amplitude of tides reaching 2 m makes any information available on animals with diurnal dispersal cycles such as copepods extremely precious. Furthermore, the lack of knowledge on these crustaceans is obvious and lags behind that of numerous other meiobenthic taxa and planktonic calanoids. Actually, most publications do not reach the species level and are limited to determining densities. This i...

Crystals

The biomimetic synthesis of a ZnO/C nanocomposite has been achieved using the egg white-assisted ... more The biomimetic synthesis of a ZnO/C nanocomposite has been achieved using the egg white-assisted self-combustion method. The characterization of this composite has been carried out using different techniques, such as XRD, FTIR, Raman, SEM/EDS and TEM. A comparative study was conducted between ZnO in the form of this composite and pristine ZnO, which was prepared via the same procedures but without the egg white. The resulting ZnO had a hexagonal structure, similar to wurtzite, with a P63mc space group. When this egg white method was used to produce a ZnO-based material, a ZnO/C nanocomposite was developed, and the ZnO’s crystallite size was significantly decreased. The structural properties—including the unit cell volume, strain, atom displacement and dislocation density—of this ZnO crystal are increased as a result of the presence of a C atom. On the other hand, the length of the Zn–O bond is reduced by the presence of the C atom. Results derived from a combination of Raman, FTIR, ...

Separations

Rosmarinus officinalis or Rosemary is a highly valued medicinal vegetal, owing to its notable ant... more Rosmarinus officinalis or Rosemary is a highly valued medicinal vegetal, owing to its notable antispasmodic, anti-inflammatory, and antibacterial properties. In the current work, we aimed to identify the chemical components of the essential oil (EO) of R. officinalis and evaluate its biological properties using an in vitro approach. High performance liquid chromatography time-of-flight mass spectrometry (HPLC-TOF-MS) was utilized to analyze of the hydro-methanolic extract (HME), while gas chromatography–mass spectrometry (GC/MS) was considered during the analysis of the EO’s chemical composition. The antioxidant abilities of HME and the EO were assessed using diverse tests (DPPH, ABTS, GOR, CUPRAC, and FRAP). The anti-enzymatic properties were tested by the inhibition of cholinesterases, α-glucosidase, and tyrosinase enzyme. The HPLC-TOF-MS displayed the existence of flavonoids like luteolin glucuronide I and II, and a few known hydroxycinnamic acids. The EO contained three major co...

Journal of Vinyl and Additive Technology

Undoped and doped polyvinyl chloride (PVC) with zinc, nickel and cobalt oxides, ZnO/[(1−x)NiO/xCo... more Undoped and doped polyvinyl chloride (PVC) with zinc, nickel and cobalt oxides, ZnO/[(1−x)NiO/xCo3O4], composites were fabricated using co‐precipitation and casting techniques. The different phases present in the nanofiller ZnO/[(1−x)NiO‐xCo3O4] mixed oxides were determined using synchrotron x‐ray diffraction technique. X‐ray diffraction, scanning electron microscopy (SEM) images and energy dispersive spectroscopy (EDS) analysis techniques were used to investigate the structure, composition, and morphology of pure and loaded PVC with nanofiller oxides. In general, compared with pure PVC, the absorbance was greatly enhanced, especially in the UV region, upon loading ZnO/[(1−x)NiO‐xCo3O4], but it changed irregularly with the cobalt oxide (Co3O4) content (x). The direct and indirect optical band gaps of pristine PVC (4.14, 4.12 eV) reduced irregularly to minimum values 3.97 and 3.23 eV respectively for the polymer doped with ZnO/[0.3NiO/0.7Co3O4]. The refractive index was enhanced in t...

Journal of Electronic Materials