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- 저자 : Dina S. Ahmed (검색결과 4 건)
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Dina E. Tobbala,Ahmed S. Rashed,Bassam A. Tayeh 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.82 No.2
Zinc-rich epoxy (ZRE) is used to overcome corrosion problems in reinforced concrete (RC) beams and coat steel rebars to protect them from humidity and chlorides. An extra coating layer of Sikadur-31 epoxy (SDE) is utilised to increase bond strength because the use of ZRE reduces the bond strength between concrete and steel rebars. However, the low melting point of SDE indicates that concrete specimens are vulnerable to fire. An experimental investigation on flexural performance of RC beams incorporating ZRE-SDE coating of steel rebars that were destroyed by fire is performed in this study. Twenty beams of five concrete mixes with different cementitious contents were tested to compare fire exposure for coated and uncoated rebars of the same beams at room temperature and determine the optimal cementitious content. Scanning electron microscopy (SEM) was also applied to investigate characteristics of fired mixture samples. Results showed that the use of SDE-ZRE at room temperature improves flexural strengths of the five mixes compared with uncoated rebars with percentages ranging from 8.5% to 12.3%. All beams with SDE-ZRE lost approximately 50% of their flexural strength due to firing. Moreover, the mix incorporating SF (silica fume) of 15% and cement content of 400 kg/m3 introduces optimum behaviour compared with other mixes. All results were supported and verified by the SEM analysis and compressive strength of cubic specimens of the same mixes.
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Fatma M. Abdel Bar,Dina S. Ibrahim,Sahar R. Gedara,Mohammed S. Abdel-Raziq,Ahmed M. Zaghloul 한국생약학회 2018 Natural Product Sciences Vol.24 No.4
The root-knot nematode, Meloidogyne incognita caused a serious damage to many plants. The phenolic components of the leaves of Schinus terebinthifolius were investigated as potential nematicidal agents for M. incognita. Nine compounds were isolated and characterized as viz., 1,2,3,4,6-pentagalloyl glucose (1), kaempferol-3-O-a-L-rhamnoside (Afzelin) (2), quercetin-3-O-a-L-rhamnoside (Quercetrin) (3), myricetin (4), myricetin-3-O-a-L-rhamnoside (Myricetrin) (5), methylgallate (6), protocatechuic acid (7), quercetin (8), and gallic acid (9) using nuclear magnetic resonance (NMR) spectroscopy. Compound 1 showed pronounced nematicidal activity compared to Oxamyl as a positive control. It showed the lowest eggs-hatchability (34%) and the highest mortality in nematode population (21% after 72 hours of treatment) at a concentration of 200 mg/mL. It exhibited the best suppressed total nematode population, root galling and number of eggmasses in infected tomato plants. The total carbohydrates and proteins were also significantly induced by 1 with reduction in total phenolics and increase in defense-related proteins. Thus, compound 1 could be a promising, more safe and effective natural nematicidal agent for the control of root-knot nematodes.
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Morphological study of porous aromatic schiff bases as a highly effective carbon dioxide storages
Rehab Hammoda,Naser Shaalan,Mohammed H. Al-Mashhadani,Dina S. Ahmed,Rahimi M. Yusop,Ali H. Jawad,Emad Yousif 한국분석과학회 2023 분석과학 Vol.36 No.5
Carbon dioxide (CO2) capture and storage is a critical issue for mitigating climate change. Porous aromatic Schiff base complexes have emerged as a promising class of materials for CO2 capture due to their high surface area, porosity, and stability. In this study, we investigate the potential of Schiff base complexes as an effective media for CO2 storage. We review the synthesis and characterization of porous aromatic Schiff bases materials complexes and examine their CO2 sorption properties. We find that Schiff base complexes exhibit high CO2 adsorption capacity and selectivity, making them a promising candidate for use in carbon capture applications. Moreover, we investigate the effect of various parameters such as temperature, and pressure on the CO2 adsorption properties of Schiff base complexes. The Schiff bases possessed tiny Brunauer-Emmett- Teller surface areas (4.7-19.4 m2/g), typical pore diameters of 12.8-29.43 nm, and pore volumes ranging from 0.02-0.073 cm3/g. Overall, our results suggest that synthesized complexes have great potential as an effective media for CO2 storage, which could significantly reduce greenhouse gas emissions and contribute to mitigating climate change. The study provides valuable insights into the design of novel materials for CO2 capture and storage, which is a critical area of research for achieving a sustainable future.
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EL-Taher Eman M. M.,El-Sherei Moshera M.,El Dine Riham Salah,ElNaggar Dina M.Y.,Khalil Wagdy K. B.,Kassem Salwa M.,Elkhateeb Ahmed,Kassem Mona E. S. 경희대학교 융합한의과학연구소 2022 Oriental Pharmacy and Experimental Medicine Vol.22 No.1
From the phenolic profile of Acacia pennata L. leaves hydromethanolic extract, nine flavonoids were tentatively character- ized (liquid chromatography-electrospray ionization mass spectrometry), of which Kaempferol 3,7-di-O-hexoside, Apigenin 6,8-di-C-hexoside, Luteolin-6-C-pentoside-8-C-hexoside, Apigenin-6-C-hexoside-8-C-pentoside and Apigenin-6-C-pento- side-8-C-hexoside were detected for the first time from the plant. Three doses of the plant extract (12.5, 25 and 50 mg/kg bw/d, four weeks treatment) were used to assess its protective effect against acetominophen induced genotoxicity in hepatic cells of male rats (2 g/kg bw twice per week). A. pennata extract and Acetominophen treated animal groups attenuated DNA damage rates (Comet assay) by 5.6, 6.2 and 6.4% for the three doses, respectively, compared with the acetaminophen treated and untreated groups by 21.2% and 5.8%, respectively. It also decreased DNA fragmentation, significantly down-regulate the expression of p53 tumour suppressor gene and mdr1b multidrug resistance gene [real-time PCR (qPCR)] and ROS genera- tion rates induced by Acetaminophen by 715.4, 453.8 and 376.9% in rats in a dose dependant effect. The results highlighted the DNA protection potential of A. pennata phytoconstituents from drug abuse harmful effects.
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