Papers by Mohamed Mahmoud
Scientific Reports
Most dye stuffs and coloring materials are mainly categorized as hazardous pollutants in water ef... more Most dye stuffs and coloring materials are mainly categorized as hazardous pollutants in water effluents due to their nature as non-biodegradable, highly toxic and extremely carcinogenic. For this reason, rapid and efficient eradication of waste dyes from wastewaters before discharging into water streams must be accomplished by an acceptable approach as adsorption technique. Therefore, the present study is aimed and devoted to synthesize a novel nanobiosorbent from three different constituents, gelatin (Gel) as a sustainable natural product, graphene oxide (GO) as an example of highly stable carbonaceous material and zirconium silicate (ZrSiO4) as an example of combined metal oxides for the formation of Gel@GO-F-ZrSiO4@Gel by using formaldehyde (F) as a cross-linkage reagent. Several characterization techniques as FT-IR were employed to identify the incorporated surface reactive Functionalities in Gel@GO-F-ZrSiO4@Gel as –OH, =NH, –NH2, –COOH and C=O, etc. The morphology for particle...
2010 Proceedings IEEE INFOCOM, 2010
In multi-hop wireless networks, the mobile nodes usually act as routers to relay packets generate... more In multi-hop wireless networks, the mobile nodes usually act as routers to relay packets generated from other nodes. However, selfish nodes do not cooperate but make use of the honest ones to relay their packets, which has negative effect on fairness, security, and performance of the network. In this paper, we propose a novel incentive mechanism to stimulate cooperation in multi-hop wireless networks. Fairness can be achieved by using credits to reward the cooperative nodes. The overhead can be significantly reduced by using a cheating detection system (CDS) to secure the payment. Extensive security analysis demonstrates that the CDS can identify the cheating nodes effectively under different cheating strategies. Simulation results show that the overhead of the proposed incentive mechanism is incomparable with the existing ones.
Saudi Journal of Biological Sciences, 2021
By using the indigenous microorganisms of the polluted environment to be treated, bioremediation ... more By using the indigenous microorganisms of the polluted environment to be treated, bioremediation can be a successful strategy. PCR and RT-PCR molecular techniques were applied to examine the evolution of fungal isolates through putative genes f ligninolytic enzymes like lignin peroxidase (LiP), laccase (LaC), manganese peroxidase (MnP), and cellulase (Cx) as a response to polluting of the environment by hydrocarbons. In this study, isolation of rhizospheric fungal isolates, molecular identification, crude oil tolerance, and enzyme excretions were demonstrated. From the date palm rhizosphere, 3 fungal isolates were isolated and characterized morphologically and molecularly by ITS ribosomal RNA (rRNA) sequencing. The isolates were identified as Aspergillus flavus AF15, Trichoderma harzianum TH07, and Fusarium solani FS12 through using the BLAST tool in NCBI. All fungal isolates showed high tolerance to crude oil and survived with various responses at the highest concentration (20%). Aspergillus flavus AF15 and Trichoderma harzianum TH07 demonstrated promising oil-degrading tolerance ability based on the dose inhibition response percentage (DIRP) of the fungal isolates. A. flavus had a powerful capacity to production Cx, LaC, LiP and MnP with a range from 83.7 to 96.3 mL. Molecularly, nine genes of the ligninolytic enzymes, cbh (cbhI.1, cbhI.1, cbhII) lcc, lig (1, 2, 4 and 6) and mnp were tested for presence and expression (by PCR and RT-PCR, respectively). PCR showed that all isolates contained all the nine genes examined, regardless of capacity to enzymes production profiles, so the presence responses of nine genes did not correlate with enzymes-production ability. Gene expression analysis shows a more diverse pattern for tested isolates for example, Aspergillus flavus AF15 had over-expression of lig and mnp genes, Fusarium solani FS12 have a weak signal with lcc gene while, Trichoderma harzianum TH07 showed moderate expression of mnp and lcc genes. The power of the transcription of the gene leads to increased enzyme secretion by fungal isolates. Fungi are important microorganisms in the clean-up of petroleum pollution. They have bioremediation highly potency that is related to their diverse production of these catalytic enzymes.
Journal of Environmental Protection, 2019
The main objective of this paper is to study the removal of Cadmium(II), Lead(II), Chromium(VI), ... more The main objective of this paper is to study the removal of Cadmium(II), Lead(II), Chromium(VI), and Mercury(II) ions by sorption onto different natural and synthetic nanoparticles. Special attention has been given to the application of fish bone in nanoform as a useful, inexpensive and eco-friendly alternative material. A comparison between natural hydroxyapatite (fish bone), synthetic hydroxyapatite nanoparticles (HAP) and alginate-hydroxyapatite composite (Alg/Hap) to assess their removal efficiencies to remediate the selected heavy metals has been done. Surface characterization by using different techniques has also been performed to understand the influence of surface characteristics of the adsorbent materials in the removal process. Different parameters (pH, contact time, mass dose and metal ion concentration) have been examined to identify the optimum conditions for remediation of different metals from polluted water. The potential applications of the biosorbents for removal and sorption of these metal ions from seawater and wastewater samples were also investigated and evaluated.
Biotechnology & Biotechnological Equipment, 2018
Metallic gold nanoparticles (AuNPs) were prepared and stabilised with henna (Lawsonia inermis) ex... more Metallic gold nanoparticles (AuNPs) were prepared and stabilised with henna (Lawsonia inermis) extract. The synthesis of AuNPs was characterised by ultraviolet-visible (UV-Vis) spectrophotometry, transmission electron microscopy (TEM), scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS), dynamic light scattering and Fourier-transform infrared spectroscopy (FTIR). This study also investigated the degradation of dichlorodiphenyltrichloroethane (DDT) using AuNPs. The initial concentration of DDT was either 10 or 20 mg/L. In our study, the highest percentage of DDT degradation was obtained when the initial DDT concentration was 20 mg/L. It reached a maximum of 64.1% at 10 mg/L and 77.4% at 20 mg/L after 72 h. DDT degradation was determined using UV-Vis spectrophotometry, FTIR and gas chromatography-mass spectrometry (GC/MS). The GC/MS spectra displayed five peaks related to the DDT degradation products: DDT, dichlorodiphenyldichloroethene (DDE), dichlorodiphenyldichloroethane (DDD), dichlorodiphenylmethane (DDM) and dichlorophenylethane (DCE). Our results indicate that AuNPs had high degradation rates for DDT, which implies that they have potential applications as metal nanoparticles for environmental clean-up.
Journal of Special Education and Rehabilitation, 2016
The implementation of Individual Educational Plans (IEPs) for children with intellectual disabili... more The implementation of Individual Educational Plans (IEPs) for children with intellectual disabilities was investigated at mainstream boys' schools in Riyadh. Qualitative data collected from interviews with 20 IEP team members, supplemented by content analysis of documentary data from a key policy document, provide rare insights into the practices and perspectives of the IEP teams working in mainstream Saudi schools. A clear discrepancy was identified between the Regulations of Special Education Institutes and Programmes (RSEIP) policy document and its implementation. Team members were also found to be unsure of their individual roles stipulated by the RSEIP document and were therefore not fulfilling these duties. Bronfenbrenner's ecological theory enables analysis of child development at different levels of society, affecting the implementation of IEPs and informing strategies to overcome barriers to implementation. This framework highlights discrepancies between policy and practice, and the major barriers to IEP implementation: parental involvement; structural support; negative attitudes; and school level. This demonstrates that development in policy and practice is required in five major areas: building collaborative teamwork; legal and administrative matters; appropriate assessment; curriculum development; and the coordination between the MoE, DGSE, mainstream schools and parents in relation to IEPs. 
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Papers by Mohamed Mahmoud