School of Basic Sciences
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Basic Science is the field that can answer fundamental questions about our world, and lead to wide-ranging applications, tremendous benefits, and value. This field is designed for those who hold a passion for science and who want to make real contributions to different fields and industries.
At GU, we created the perfect environment for our students to spark their curiosity and encourage their passion for knowledge and prepare them for a challenging and rewarding career.
This field offers 3 programs; Nanoscience & Technology, Petroleum & Mining Geology and Molecular Biotechnology. All the programs are delivered through an innovative teaching method, with the support of 9 of the most advanced labs and workshops in the MENA region.
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- PublicationMetadata onlyA Review of Chemotherapy and Photodynamic Therapy for Lung Cancer Treatment(Bentham Science, 2021) El-Newishy, Ahmed El-Hussein; Manoto, Sello L.; Ombinda-Lemboumba, Saturnin; Alrowaili, Ziya A.; Mthunzi-Kufa, PatienceCancer is among the leading causes of mortality and morbidity worldwide. Among the different types of cancers, lung cancer is considered to be the leading cause of death related to cancer and the most commonly diagnosed form of such disease. Chemotherapy remains a dominant treatment modality for many types of cancers at different stages. However, in many cases, cancer cells develop drug resistance and become nonresponsive to chemotherapy, thus, necessitating the exploration of alternative and /or complementary treatment modalities. Photodynamic Therapy (PDT) has emerged as an effective treatment modality for various malignant neoplasia and tumors. In PDT, the photochemical interaction of light, Photosensitizer (PS), and molecular oxygen produces Reactive Oxygen Species (ROS), which induces cell death. Combination therapy, by using PDT and chemotherapy, can promote synergistic effects against this fatal disease with the elimination of drug resistance, and enhancement of the efficacy of cancer eradication. In this review, we give an overview of chemotherapeutic modalities, PDT, and the different types of drugs associated with each therapy. Furthermore, we also explored the combined use of chemotherapy and PDT in the course of lung cancer treatment and how this approach could be the last resort for thousands of patients that have been diagnosed with this fatal disease.
- PublicationOpen AccessA Single Short ‘Tone Burst’ Results in Optimal Drug Delivery to Tumours Using Ultrasound-Triggered Therapeutic Microbubbles(MDPI, 2022-03-11) Ingram, Nicola; McVeigh, Laura E.; Abou-Saleh, Radwa; Batchelor, Damien V. B.; Loadman, Paul M.; McLaughlan, James R.; Markham, Alexander F.; Evans, Stephen D.; Coletta, P. LouiseAdvanced drug delivery systems, such as ultrasound-mediated drug delivery, show great promise for increasing the therapeutic index. Improvements in delivery by altering the ultrasound parameters have been studied heavily in vitro but relatively little in vivo. Here, the same therapeutic microbubble and tumour type are used to determine whether altering ultrasound parameters can improve drug delivery. Liposomes were loaded with SN38 and attached via avidin: biotin linkages to microbubbles. The whole structure was targeted to the tumour vasculature by the addition of anti-vascular endothelial growth factor receptor 2 antibodies. Tumour drug delivery and metabolism were quantified in SW480 xenografts after application of an ultrasound trigger to the tumour region. Increasing the trigger duration from 5 s to 2 min or increasing the number of 5 s triggers did not improve drug delivery, nor did changing to a chirp trigger designed to stimulate a greater proportion of the microbubble population, although this did show that the short tone trigger resulted in greater release of free SN38. Examination of ultrasound triggers in vivo to improve drug delivery is justified as there are multiple mechanisms at play that may not allow direct translation from in vitro findings. In this setting, a short tone burst gives the best ultrasound parameters for tumoural drug delivery.
- PublicationMetadata onlyAnti-proliferative effect of chitosan nanoparticles (extracted from crayfish Procambarus clarkii, Crustacea: Cambaridae) against MDA-MB-231 and SK-BR-3 human breast cancer cell lines.(Elsevier, 2019) Taher, F. A.; Ibrahim, S. A.; El-Aziz, A. A.; Abou El-Nour, M. F.; El-Sheikh, M. A.; El-Husseiny, N.; Mohamed, Mona MostafaActually, the most common cancer in women is the breast cancer which is the second most widespread cancer overall. In 2018, there were over two million new cases of women breast cancer. Particularly, we tried to extract chitosan from crayfish Procambarus clarkii, Crustacea: Cambaridae, by N-deacetylation of chitin. The chemical structure of chitosan was characterized by Fourier transform infrared (FT-IR) spectroscopy. Also DDA was calculated from FT-IR and ultraviolet spectrophotometry data. Chitosan nanoparticles were prepared using a ball-milling technique. The as-prepared chitosan nanoparticles were characterized by transmission electron microscopy, dynamic light scattering as well as zeta potential. The cytotoxicity of chitosan and its nanoparticles (50 and 100 μg/mL) against human breast cancer (SK BR3 and MDA-MB-231 cell lines) was evaluated. MTT assay asserts the significant inhibitory action of both chitosan and its nanoparticles on the proliferation of human breast cancer cells in vitro. Chitosan nanoparticles had more anti-proliferative effects on MDA-MB-231 and SK-BR-3 cell lines than its corresponding chitosan. Although, chitosan nanoparticles, that has higher DDA, had a higher cytotoxic activity against human breast cancer MDA-MB-231 and SK-BR-3 cell lines in vitro. Eventually, chitosan and its nanoparticles can be considered as a promising natural compounds in human breast cancer treatment.
- PublicationOpen AccessBiocontrol of okra-rot-causing Cochliobolus spicifer-CSN-20 using secondary metabolites of endophytic fungi associated with Solenostemma arghel(Elsevier, 2022-04-21) Abdel-Motaal, Fatma F.; Kamel, Noha M.; El-Sayed, Magdi Abdel-Radi; Abou-Ellail, MohamedRot disease is responsible for serious economic losses related to okra (Abelmoschus esculentus) crops cultivated in Upper Egypt. Colonies with a consistent morphology were isolated from the infected okra stems and leaves and subjected to morphological and molecular examinations. The causal pathogen was identified as Cochliobolus spicifer based on morphological fungus descriptions, as well as on the amplified 28S rDNA and internal transcribed spacer region (ITS) sequences, which showed 99%–100% similarity to the sequences of C. spicifer-CSN-20 strains. The volatile and non-volatile organic compounds (VOCs and n-VOCs, respectively) produced by the endophytic fungi that are associated with the medicinal plant Solenostemma arghel, namely Fusarium solani-F4-1007, Penicillium verrucosum-F2-1006, and Aspergillus terreus-F5-1008, inhibited the growth of the C. spicifer pathogen by 34.2%,31.4%, and 30.5%, respectively. In total,27 VOCs were identified by GC/MS, among which eight were specific to A. terreus-F5-1008, eight to P. verrucosum-F2-1006, and three to F. solani-F4-1007, whereas nine VOCs were commonly produced by the three endophytic fungi. Moreover, F. solani-F4-1007-produced VOCs and n-VOCs exhibited the highest antifungal activity, with 37.27% and 37.1% inhibition against C. spicifer colony growth, respectively. The potent antifungal VOCs produced by F. solani-F4-1007 were identified as 3,4-dihydro-2 h-1,5-(3″-t-butyl) benzodioxepine, 4-(2-hydroxyethyl) phenol, and phenylethyl alcohol using GC/MS. Therefore, F. solani-F4-1007 was tested as a potential biocontrol agent against C. spicifer-CSN-20 using an in-planta assay. Okra plants treated with endophytic F. solani-F4-1007did not show any disease symptoms, whereas those that were not treated with F. solani-F4-1007 exhibited severe disease symptoms when challenged with inoculation of the C. spicifer pathogen. Our results demonstrated the contribution of the endophytic fungus F. solani-F4-1007 as a potential biocontrol agent against the C. spicifer pathogen, to improve okra growth.
- PublicationOpen AccessBiocontrol of Sweet Melon Fruit rot Caused by Fusarium solani using an Endophytic Fungus Isolated from the Medicinal Plant Solenostemma arghel(Hashemite University, 2021-09) Abdel-Motaal, Fatma F.; Kamel, Noha M.; El-Sayed, Magdi Abdel-Radi; Abou-Ellail, MohamedThe fruit rot disease of sweet melon is responsible for serious of economic crop losses that have occurred sporadically in Aswan, Egypt recently. The symptoms appeared as water-soaking lesion which advanced to the rotting of the fruit surface. White mycelial mats with brown color inside appear on the lesion at the surface of the fruit. Disease symptoms, morphological and mycological characteristics, pathogenicity and molecular identification, indicated as Fusarium solani, are the disease causative. When healthy fruits of sweet melon sprayed with spore suspension of the isolated F. solani, the disease symptoms appeared as white spot, which enlarged and turned brown. Dual culture techniques showed that the endophytic fungi, Aspergillus terreus, Fusarium solani and Penicillium verrucosum isolated from the medicinal plant Solenostemma arghel inhibited the pathogen growth in variable levels. The extract of ethyl acetate of the endophytic fungal was found to be active against Fusarium solani. The ethyl acetate fractions of Penicillium verrucosum inhibited the pathogen growth by 47% while A. terreus, and F. solani showed inhibition percentage of 45% and 40%, respectively.
- PublicationOpen AccessBioremoval capacity of phenol by some selected endophytic fungi isolated from Hibiscus sabdariffa and batch biodegradation of phenol in paper and pulp effluents(Tehran University of Medical Sciences, 2021-06-15) Khali, Doaa Montaser Ahmed; Massoud, Mohamed Salah; El-Zayat, Soad A.; El-Sayed, Magdi Abdel-RadiBackground and Objectives: The use of endophytic fungi for management of phenol residue in paper and pulp industries has been shown as cost-effective and eco-friendly approach. In this study, isolation of endophytic fungi from roots, stems, and leaves of Hibiscus sabdariffa was conducted. Additionally, the isolated fungi were examined for their ability to degrade phenol and its derivatives in paper and pulp industrial samples, using different growth conditions.
- PublicationMetadata onlyCarbon metabolic adjustment in soybean nodules in response to phosphate limitation: A metabolite perspective(Elsevier, 2022-02-02) Abdelrahman, Mostafa; Tran, Lam Son Phan; Sulieman, Saad A.The necessity to gain deep insights regarding the overall metabolic efficiency of soybean functional acclimation to tackle phosphate (Pi) starvation has led us to discuss the current knowledge on the carbon (C) metabolic changes in soybean nodules under such Pi stress conditions in this review. Soybean possesses numerous coping strategies to conserve Pi utilization, while decreasing the C cost to promote nodule function during Pi stress. This could be achieved through the modulation of carbohydrate importation, mobilization of storage reserves, modification of respiratory pathways and exportation of nitrogenous (N) products. Under such circumstances, soybean regulates the C partitioning among the various nutrient-acquiring structures and the C flux through different metabolic pathways (primary and secondary). However, substantial genetic variation leading to nodule acclimation to Pi stress is notable and dependent on the crop genotypes and/or rhizobial strains that are in symbiosis. Several Pi deficiency-induced responses (e.g., mycorrhizal association, exudative burst and secondary metabolism) can act to increase the Pi levels in nodules, which are, unavoidably, often associated with a heavy burden to the overall C budget of the host. Alternative non-adenylate respiratory pathways (e.g., glycolytic bypass) and ureide export (i.e., less amide transport) are metabolically less expensive, and thus more favorable during Pi stress.
- PublicationOpen AccessChemical and spectroscopic characterization of tourmaline from the ancient Roman mines in the Eastern Desert of Egypt(Springer Nature, 2022-01-25) Omar, Sayed M. A.; Surour, Adel AbdullahTourmaline occurrences are found in the Eastern Desert of Egypt, particularly at the Wadi El-Gemal area, which is the locality of famous beryl mines dated back to the Roman times including the so-called “Cleopatra’s Emerald Mines”. The collected tourmaline occurs in beryl-rich pegmatites and quartz veins. Infrared data of tourmaline indicate that dravite from three localities (Wadi Sikait, Wadi Um Sleimat and Wadi Um Addebbaa) can be distinguished based on the nature of the OH group and its vibrational bands. Also, reflectance spectra of fresh and altered dravite are distinguishable. Mineral inclusions (mostly hafnon zircon and REE-bearing apatite and monazite) in dravite affects the FTIR (Fourier transform infrared) spectra. Such spectra show influence of cationic substitutions in dravite, particularly M²⁺at the X-site and M³⁺ at the Y-site. Spectrometric measurements suggest that radioelements in tourmaline are not considerably high, whereas high radioactivity is restricted to the pegmatite bodies away from the metasomatic front with the serpentinite country rocks.
- PublicationOpen AccessChromosome-scale haplotype-phased genome assemblies of the male and female lines of wild asparagus (Asparagus kiusianus), a dioecious plant species(Oxford Acadmic, 2022-01-18) Abdelrahman, Mostafa; Shirasawa, Kenta; Ueta, Saki; Murakami, Kyoko; Kanno, Akira; Isobe, SachikoAsparagus kiusianus is a disease-resistant dioecious plant species and a wild relative of garden asparagus (Asparagus officinalis). To enhance A. kiusianus genomic resources, advance plant science, and facilitate asparagus breeding, we determined the genome sequences of the male and female lines of A. kiusianus. Genome sequence reads obtained with a linked-read technology were assembled into four haplotype-phased contig sequences (∼1.6 Gb each) for the male and female lines. The contig sequences were aligned onto the chromosome sequences of garden asparagus to construct pseudomolecule sequences. Approximately 55,000 potential protein-encoding genes were predicted in each genome assembly, and ∼70% of the genome sequence was annotated as repetitive. Comparative analysis of the genomes of the two species revealed structural and sequence variants between the two species as well as between the male and female lines of each species. Genes with high sequence similarity with the male-specific sex determinant gene in A. officinalis, MSE1/AoMYB35/AspTDF1, were presented in the genomes of the male line but absent from the female genome assemblies. Overall, the genome sequence assemblies, gene sequences, and structural and sequence variants determined in this study will reveal the genetic mechanisms underlying sexual differentiation in plants, and will accelerate disease-resistance breeding in garden asparagus.
- PublicationOpen AccessComprehensive Metabolite Profiling in Genetic Resources of Garlic (Allium sativum L.) Collected from Different Geographical Regions(MDPI, 2021-03-05) Abdelrahman, Mostafa; Hirata, Sho; Mukae, Takuya; Yamada, Tomohiro; Sawada, Yuji; El-Sayed, Magdi Abdel-Radi; Yamada, Yutaka; Sato, Muneo; Hirai, Masami Yokota; Shigyo, MasayoshiGarlic (Allium sativum) is the second most important Allium crop that has been used as a vegetable and condiment from ancient times due to its characteristic flavor and taste. Although garlic is a sterile plant that reproduces vegetatively through cloves, garlic shows high biodiversity, as well as phenotypic plasticity and environmental adaptation capacity. To determine the possible mechanism underlying this phenomenon and to provide new genetic materials for the development of a novel garlic cultivar with useful agronomic traits, the metabolic profiles in the leaf tissue of 30 garlic accessions collected from different geographical regions, with a special focus on the Asian region, were investigated using LC/MS. In addition, the total saponin and fructan contents in the roots and cloves of the investigated garlic accessions were also evaluated. Total saponin and fructan contents did not separate the garlic accessions based on their geographical origin, implying that saponin and fructan contents were clone-specific and agroclimatic changes have affected the quantitative and qualitative levels of saponins in garlic over a long history of cultivation. Principal component analysis (PCA) and dendrogram clustering of the LC/MS-based metabolite profiling showed two major clusters. Specifically, many Japanese and Central Asia accessions were grouped in cluster I and showed high accumulations of flavonol glucosides, alliin, and methiin. On the other hand, garlic accessions grouped in cluster II exhibited a high accumulation of anthocyanin glucosides and amino acids. Although most of the accessions were not separated based on country of origin, the Central Asia accessions were clustered in one group, implying that these accessions exhibited distinct metabolic profiles. The present study provides useful information that can be used for germplasm selection and the development of new garlic varieties with beneficial biotic and abiotic stress-adaptive traits.
- PublicationOpen AccessDefective cytokinin signaling reprograms lipid and flavonoid gene-to-metabolite networks to mitigate high salinity in Arabidopsis(National Academy of Science, 2022-11-23) Abdelrahman, Mostafa; Nishiyama, Rie; Tran, Cuong Duy; Tran, Lam-Son PhanCytokinin (CK) in plants regulates both developmental processes and adaptation to environmental stresses. Arabidopsis histidine phosphotransfer ahp2,3,5 and type-B Arabidopsis response regulator arr1,10,12 triple mutants are almost completely defective in CK signaling, and the ahp2,3,5 mutant was reported to be salt tolerant. Here, we demonstrate that the arr1,10,12 mutant is also more tolerant to salt stress than wild-type (WT) plants. A comprehensive metabolite profiling coupled with transcriptome analysis of the ahp2,3,5 and arr1,10,12 mutants was conducted to elucidate the salt tolerance mechanisms mediated by CK signaling. Numerous primary (e.g., sugars, amino acids, and lipids) and secondary (e.g., flavonoids and sterols) metabolites accumulated in these mutants under nonsaline and saline conditions, suggesting that both prestress and poststress accumulations of stress-related metabolites contribute to improved salt tolerance in CK-signaling mutants. Specifically, the levels of sugars (e.g., trehalose and galactinol), amino acids (e.g., branched-chain amino acids and γ-aminobutyric acid), anthocyanins, sterols, and unsaturated triacylglycerols were higher in the mutant plants than in WT plants. Notably, the reprograming of flavonoid and lipid pools was highly coordinated and concomitant with the changes in transcriptional levels, indicating that these metabolic pathways are transcriptionally regulated by CK signaling. The discovery of the regulatory role of CK signaling on membrane lipid reprogramming provides a greater understanding of CK-mediated salt tolerance in plants. This knowledge will contribute to the development of salt-tolerant crops with the ability to withstand salinity as a key driver to ensure global food security in the era of climate crisis.
- PublicationMetadata onlyDefective cytokinin signaling reprograms lipid and flavonoid gene-to-metabolite networks to mitigate high salinity in Arabidopsis(National Academy of Science, 2021) Abdelrahman, Mostafa; Nishiyama, Rie; Tran, Cuong Duy; Kusano, Miyako; Nakabayashi, Ryo; Okazaki, Yozo; Matsuda, Fumio; Montes, Ricardo A. Chávez; Mostofa, Mohammad Golam; Li, Weiqiang; Watanabe, Yasuko; Fukushima, Atsushi; Tanaka, Maho; Seki, Motoaki; Saito, Kazuki; Herrera-Estrella, Luis; Tran, Lam-Son PhanCytokinin (CK) in plants regulates both developmental processes and adaptation to environmental stresses. Arabidopsis histidine phosphotransfer ahp2,3,5 and type-B Arabidopsis response regulator arr1,10,12 triple mutants are almost completely defective in CK signaling, and the ahp2,3,5 mutant was reported to be salt tolerant. Here, we demonstrate that the arr1,10,12 mutant is also more tolerant to salt stress than wild-type (WT) plants. A comprehensive metabolite profiling coupled with transcriptome analysis of the ahp2,3,5 and arr1,10,12 mutants was conducted to elucidate the salt tolerance mechanisms mediated by CK signaling. Numerous primary (e.g., sugars, amino acids, and lipids) and secondary (e.g., flavonoids and sterols) metabolites accumulated in these mutants under nonsaline and saline conditions, suggesting that both prestress and poststress accumulations of stress-related metabolites contribute to improved salt tolerance in CK-signaling mutants. Specifically, the levels of sugars (e.g., trehalose and galactinol), amino acids (e.g., branched-chain amino acids and γ-aminobutyric acid), anthocyanins, sterols, and unsaturated triacylglycerols were higher in the mutant plants than in WT plants. Notably, the reprograming of flavonoid and lipid pools was highly coordinated and concomitant with the changes in transcriptional levels, indicating that these metabolic pathways are transcriptionally regulated by CK signaling. The discovery of the regulatory role of CK signaling on membrane lipid reprogramming provides a greater understanding of CK-mediated salt tolerance in plants. This knowledge will contribute to the development of salt-tolerant crops with the ability to withstand salinity as a key driver to ensure global food security in the era of climate crisis.
- PublicationOpen AccessDesign of self-supported flexible nanostars mfe-ldh@ carbon xerogel-modified electrode for methanol oxidation(MDPI, 2021-09-13) Abdelrazek, Ghada M.; EL-Deeb, Mohamed M.; Farghali, Ahmed A.; Pérez-Cadenas, Agustín F.; Abdelwahab, AbdallaLayered double hydroxides (LDHs) have emerged as promising electrodes materials for the methanol oxidation reaction. Here, we report on the preparation of different LDHs with the hydrothermal process. The effect of the divalent cation (i.e., Ni, Co, and Zn) on the electrochemical performance of methanol oxidation was investigated. Moreover, nanocomposites of LDHs and carbon xerogels (CX) supported on nickel foam (NF) substrate were prepared to investigate the role of carbon xerogel. The results show that NiFe-LDH/CX/NF is an efficient electrocatalyst for methanol oxidation with a current density that reaches 400 mA·m−2 compared to 250 and 90 mA·cm−2 for NiFe-LDH/NF and NF, respectively. In addition, all LDH/CX/NF nanocomposites show excellent stability for methanol oxidation. A clear relationship is observed between the electrodes crystallite size and their activity to methanol oxidation. The smaller the crystallite size, the higher the current density delivered. Additionally, the presence of carbon xerogel in the nanocomposites offer 3D interconnected micro/mesopores, which facilitate both mass and electron transport.
- PublicationMetadata onlyDesign, synthesis and docking studies of new hydrazinyl-thiazole derivatives as anticancer and antimicrobial agents(Elsevier, 2022-05-20) El-Naggar, Abeer M.; Zidan, Alaa; Elkaeed, Eslam B.; Taghour, Mohammed S.; Badawi, Waleed A.Increase in the number of infections caused by pathogenic microbes in cancer patients has prompted the searcher to invest in the development of agents having dual anticancer and antimicrobial properties. The present study is concerned with synthesis and screening for anticancer and antimicrobial activity of a series of 5-hydrazinyl-2-(2-(1-(thien-2-yl)ethylidene)hydrazinyl)thiazole derivatives. The structure elucidation of the synthesized hydrazinyl thiazole derivatives was illustrated by spectroscopic and elemental analysis. All the newly synthesized compounds 5a-p were evaluated for in-vitro cytotoxic activity against breast carcinoma (MCF-7 cell line), hepatocellular carcinoma (HePG-2) and colorectal cancer (HCT-116) cell lines using MTT assay method. Compounds 5 g, 5h showed broad spectrum activity against three cancer cell lines with IC50 ranged from 3.81 to 11.34 µM in compared to the reference drug Roscovitine (IC50 = 9.32 to 13.82 µM), while compounds 5 l and 5 m were found to be more selective against HePG-2 and HCT-116 cell line (IC50 = 9.29 and 8.93 µM respectively) and compound 5j was more selective against HePG-2 and MCF-7 cell lines (IC50 = 6.73 and 10.87 µM respectively). The inhibitory activity of the most promising compounds was tested against the EGFR and ARO enzymes and were further tested for apoptosis and Annexin V/PI staining. The results of enzyme-based tests revealed that the tested compound 5j has a dual inhibitory effect on the EGFR and ARO enzymes with IC50 = 82.8 and 98.6 nM respectively in compared to the reference drugs Erlotinib and Letrozole (IC50 = 62.4 and 79 nM respectively). Furthermore, the majority of the tested hydrazinyl thiazole derivatives exhibited significant antimicrobial activity against the used pathogenic microbes species. Compounds 4b, 5h, 5j and 5 m exerted a good antibacterial and antifungal activity against all tested pathogenic microbes. Therefore, it was concluded that compounds 5 h, 5j and 5 m proved to possess dual anticancer and antimicrobial agent and may serves as a useful lead compounds in search for further modification or derivatization to give more potent and selective agents.
- PublicationMetadata onlyDipolar particles via photopolymerization of 1,6-hexanediol diacrylate miniemulsion template tailored with oppositely-charged polymerizable surfactants(Elsevier, 2021-12-15) Essawy, Hisham A.; Dyab, Amro K. F.; Abd El-Mageed, Ahmed I. A.A new technique was developed for producing dipolar colloidal particles via miniemulsification of 1,6-hexandiol diacrylate (HDDA), which was stabilized by a non-ionic surfactant, in presence of a UV initiator, and doped with different oppositely-charged polymerizable surfactants (surfmers). The surfmers were chosen of poor miscibility with water to ensure their existence at the interface between the phases while the charged moieties are exposed toward the aqueous phase. Thereafter, the miniemulsion was mixed with agarose medium, and gelation was accomplished instantly to arrest the oil drops while the charged surfmers are immobilized on their surfaces. The drops were exposed to DC-field for polarization of the charges whereas UV radiation was applied simultaneously to trigger polymerization. The well-known particle nucleation in miniemulsion systems as well as polarizability of the charged moieties of the surfmers under the effect of the field and complete conversion of UV-initiated polymerization allowed the formation of particles bearing strong dipole moment. Size and zeta potential measurements of particles confirmed the nanometric size, typical of miniemulsion technique, which was further confirmed by scanning electron microscopy (SEM). On the other hand, a net charge on the surface even in presence of both cationic and anionic surfmers, is an evidence of non-equal hemispheres of the particles under the alignment induced by the electric field. This is dependent on the molar ratio of the charged species and intensity of the electric field during polymerization. In addition, the high resistance of aqueous dispersions of the polarized particles to induced aggregation in presence of an electrolyte, compared to a weakly-polarized comparable system, approves strongly the dipolarity of the particles. Cross-polarized optical imaging of assemblies formed in presence of electrolytes indicated clusters around 30 µm in size with excellent birefringence. Nevertheless, that was not the case for the un/weakly-polarized particles, indicating the anisotropy of the particles that agrees with the expected dipolar nature. This was also supported by SEM images recorded after DC induced polarization, which showed ordered aggregates in response to the applied DC field on particles holding aligned opposite charges.
- PublicationOpen AccessEffect of pH and zeta potential of Pickering stabilizing magnetite nanoparticles on the features of magnetized polystyrene microspheres(Wiley, 2020-11-03) Shalan, Ahmed Esmail; Mohamed, Lamiaa A.; Essawy, Hisham A.; Taha, Fouad; Dyab, Amro K. F.; Abd El-Mageed, Ahmed I. A.Styrene as a monomer was emulsified in water using several magnetite nanoparticles concentration and pH values. Emulsified styrene drops were used as templates for polymerization, in presence of water soluble free radical initiator, and formation of composite particles. Styrene template drops stabilization was verified by light as well as scanning electron microscopy imaging, which ensured the participation of the particles in building up a mechanical barrier to stop oil drops coalescence. Furthermore, the produced polystyrene composites were strongly attracted to an external magnet. The difference in particles size as a function of pH was elucidated using zeta potential measurements, which indicated dominance of pH on the hydrophilicity of the particles and consequently the extent of emulsification, which in turn affected the size of the obtained microspheres. Under some circumstances, capsules were formed instead of particles. Thereby, it can be concluded that the magnetic microspheres are optimally formed at pH 2.3 independently of the magnetite content used.
- PublicationOpen AccessEffect of Unit-Cell Size on the Barely Visible Impact Damage in Woven Composites(MDPI, 2021) El-Dessouky, Hassan M.; Saleh, Mohamed Nasr; Wang, Ying; Alotaibi, Mohamed S.The effect of the weaving architecture and the z-binding yarns, for 2D and 3D woven composites on the low-velocity impact resistance of carbon fibre reinforced composites, is investigated and benchmarked against noncrimp fabric (NCF). Four architectures, namely: NCF, 2D plain weave (2D-PW), 3D orthogonal: plain (ORT-PW) and twill (ORT-TW), were subjected to 15 J impact using a 16 mm-diameter, 6.7 kg hemispherical impactor. Nondestructive techniques, including ultrasonic C-scanning, Digital Image Correlation (DIC), and X-ray computed tomography (CT) were used to map and quantify the size of the induced barely visible impact damage (BVID). The energy absorption of each architecture was correlated to the damage size: in both in-plane and in-depth directions. The 3D architectures, regardless of their unit-cell size, demonstrated the highest impact resistance as opposed to 2D-PW and the NCF. X-ray CT segmentation showed the effect of the higher frequency of the z-binding yarns, in the ORT-PW case, in delamination and crack arresting even when compared to the other 3D architecture (ORT-TW). Among all the architectures, ORT-PW exhibited the highest damage resistance with the least damage size. This suggests that the accurate design of the z-binding yarns’ path and more importantly its frequency in 3D woven architectures is essential for impact-resistant composite structures.
- PublicationMetadata onlyEncapsulation of folic acid (vitamin B9) into sporopollenin microcapsules: Physico-chemical characterisation, in vitro controlled release and photoprotection study(Elsevier, 2021-06-24) Mohammed, Al-Shymaa Y.; Dyab, Amro K. F.; Taha, Fouad; Abd El-Mageed, Ahmed I. A.Folic acid (FA) is a crucial vitamin for all living creatures. However, it is susceptible to degradation under pH, heat, ultraviolet (UV) and day sunlight conditions, resulting in lowering its bioavailability. Therefore, a versatile protective encapsulation system for FA is highly required to overcome its inherent instability. We report the use of the robust Lycopodium clavatum sporopollenin (LCS) microcapsules, extracted from their natural micrometer-sized raw spores, for FA microencapsulation. The physico-chemical characterisation of the LCS microcapsules are comprehensively investigated before and after the microencapsulation using SEM, elemental, CLSM, FTIR, TGA/DTG and XRD analyses, revealing a successful FA encapsulation within the LCS in an amorphous form. The phenylpropanoid acids, responsible for the UV protection and the autofluorescence of the LCS, were found in the LCS as evidenced by FTIR analysis. TGA/DTG results revealed that the hemi-cellulose and cellulose are the major component of the LCS. A controlled and sustained release of FA from FA-loaded LCS were achieved where the release profile of FA-loaded LCS was found to be pH-dependent. The percentages of cumulative FA released after 10 h at 37 ± 0.5 °C were 45.5% and 76.1% in pH 1.2 and 7.4, respectively, ensuring controlled and slow release in simulated physiological conditions. The FA release kinetic studies indicated the prevalence of the Fickian diffusion mechanism in pH 1.2, while anomalous non-Fickian transport was ascribed for FA release in pH 7.4. The in vitro cytotoxicity assay revealed that the obtained formulations were biocompatible against the human skin fibroblast (HSF) cell line. The versatile LCS microcapsules exhibited intriguing photostability for FA under UV or sunlight irradiation. Concretely, the obtained FA sustained delivery and photoprotection properties of these LCS microcapsules validate their multifunctional characteristics, opening up intriguing applications in oral and topical drug delivery as well as in food industry.
- PublicationMetadata onlyEnhanced photocatalytic and antimicrobial performance of a multifunctional Cu-loaded nanocomposite under UV light: theoretical and experimental study(Royal Society of Chemistry, 2022-05-18) Abd Elkodous, M. ; Abdel Maksoud, M. I. A. ; Alias, Nurhaswani; Abdelsalam, Hazem; Ibrahim, Medhat A.; Elsayed, Mohamed A.; Kawamura, Go; Lockman, Zainovia; Tan, Wai Kian; Matsuda, Atsunori; El-Khawaga, Ahmed Mohamed; El-Sayyad, Gharieb SaiedDue to modern industrialization and population growth, access to clean water has become a global challenge. In this study, a metal–semiconductor heterojunction was constructed between Cu NPs and the Co0.5Ni0.5Fe2O4/SiO2/TiO2 composite matrix for the photodegradation of potassium permanganate, hexavalent chromium Cr(VI) and p-nitroaniline (pNA) under UV light. In addition, the electronic and adsorption properties after Cu loading were evaluated using density functional theory (DFT) calculations. Moreover, the antimicrobial properties of the prepared samples toward pathogenic bacteria and unicellular fungi were investigated. Photocatalytic measurements show the outstanding efficiency of the Cu-loaded nanocomposite compared to that of bare Cu NPs and the composite matrix. Degradation efficiencies of 44% after 80 min, 100% after 60 min, and 65% after 90 min were obtained against potassium permanganate, Cr(VI), and pNA, respectively. Similarly, the antimicrobial evaluation showed high ZOI, lower MIC, higher protein leakage amount, and cell lysis of nearly all microbes treated with the Cu-loaded nanocomposite.
- PublicationOpen AccessEnhancement of Labneh Quality by Laser-Induced Modulation of Lactocaseibacillus casei NRRL B-1922(MDPI, 2022-03-18) Elshaghabee, Fouad M. F.; Mohamed, Mahmoud S. M.; EL-Newishy, Ahmed El-HusseinLabneh is positioned in the top ranking of the bestselling dairy products all over the world due to its health benefits and delicious taste. Labneh production depends mainly on probiotic bacteria in the fermentation of milk. Probiotic bacteria have many health benefits, which are driven by their selective bioactive metabolites that quantitively affect the fermentation products. The current investigation aimed to study the implementation of photobiomodulation through the irradiation of Lacticaseibacillus casei NRRL-B-1922 by a He–Ne laser (630 nm) with different laser doses (3, 6 & 12 J/cm2) prior to milk fermentation. This procedure sought to improve the probiotic bacteria’s activities while enhancing the labneh’s characteristics and consequently produce a more favorable labneh product with better marketing qualities. The photobiostimulated bacterial starter was found to induce increased titratable acidity with the moisture reduction of the labneh product under cold storage conditions for 20 days. The effect was most prominent when using a 12 J/cm2 laser dose. The flavor-aiding components, mainly diacetyl and acetaldehyde compounds, and sensory scores were increased in the labneh produced by irradiated L. casei when compared to the non-radiated probiotic culture after storing the products under cold conditions for 20 consecutive days. Moreover, the antioxidant and proteolytic activities of labneh produced by treated L. casei (12 J/cm2 laser dose) after cold storage were significantly elevated by 41 and 14%, respectively. In conclusion, we can report significantly improved selected characteristics in the final products after the employment of photobiomodulation process, the potential application of this concept on the industrial scale, and its implications on lengthening the product shelf life with improved qualities.