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On the static stability of nonlocal nanobeams using higher-order beam theories
Eltaher, M.A.,Khater, M.E.,Park, S.,Abdel-Rahman, E.,Yavuz, M. Techno-Press 2016 Advances in nano research Vol.4 No.1
This paper investigates the effects of thermal load and shear force on the buckling of nanobeams. Higher-order shear deformation beam theories are implemented and their predictions of the critical buckling load and post-buckled configurations are compared to those of Euler-Bernoulli and Timoshenko beam theories. The nonlocal Eringen elasticity model is adopted to account a size-dependence at the nano-scale. Analytical closed form solutions for critical buckling loads and post-buckling configurations are derived for proposed beam theories. This would be helpful for those who work in the mechanical analysis of nanobeams especially experimentalists working in the field. Results show that thermal load has a more significant impact on the buckling behavior of simply-supported beams (S-S) than it has on clamped-clamped (C-C) beams. However, the nonlocal effect has more impact on C-C beams that it does on S-S beams. Moreover, it was found that the predictions obtained from Timoshenko beam theory are identical to those obtained using all higher-order shear deformation theories, suggesting that Timoshenko beam theory is sufficient to analyze buckling in nanobeams.
STATISTICAL GAUSSIAN DISTRIBUTION FUNCTION AS A DISTANCE INDICATOR TO STELLAR GROUPS
Abdel-Rahman, H.I.,Issa, I.A.,Sharaf, M.A.,Nouh, M.I.,Bakry, A.,Osman, A.I.,Saad, A.S.,Kamal, F.Y.,Essam, Essam The Korean Astronomical Society 2009 Journal of The Korean Astronomical Society Vol.42 No.4
In this paper, statistical distribution functions are developed for distance determination of stellar groups. This method depends on the assumption that absolute magnitudes and apparent magnitudes follow a Gaussian distribution function. Due to the limits of the integrands of the frequency function of apparent and absolute magnitudes, we introduce Case A, B, and C Gaussian distributions. The developed approaches have been implemented to determine distances to some clusters and stellar associations. The comparison with the distances derived by different authors reveals good agreement.
Hammam, A.S.,Youssef, M.S.K.,Radwan, Sh.M.,Abdel-Rahman, M.A. Korean Chemical Society 2004 Bulletin of the Korean Chemical Society Vol.25 No.6
Syn (or anti) cinnamaldehydeoxime (1a, b) undergoes Diels-Alder addition to tetrabromo-p-benzoquinone (2)in dry xylene in 1 : 1 and 2 : 1 molar ratios to give the mono- and diadducts 3 and 4a, b respectively. The reaction of 3 with thioamides in ethanol gave thiazoloquinoline diones 6a-d, whereas with acid amides in ethylene glycol, it gave oxazoloquinolinediones 12a-f.
Synthesis and Reactions of New Thienopyridines, Pyridothieniopyrimidines and Pyridothienotriazines
Bakhite, E.A.,Abdel Rahman, A.E.,Mohamed, O.S.,Thabet, E.A. Korean Chemical Society 2002 Bulletin of the Korean Chemical Society Vol.23 No.12
4-Aryl-3-cyano-6-(2'-thienyl)-pyridine-2(1H)-thiones(1a-c) were reacted with phenacyl bromide, chloro-N-arylacetanmides or 2-chloroacetylaminopyridine to furnish 2-functionalized 3-amino-4-aryl-6-(2'-thienyl)-thieno[2,3-b]pyridines 4a-c and 5a-c or 5d respecitively. The compounds 5a-d underwent different sequence of reactions to produce a variety of thienylpyridothienopyrimidines and, thienylpyridothienotriazines. Some of the prepared compounds were tested in vitro for their antimicrobial activities.
Yahya Zakaria Hassanein,S. S. A. Abdel-Rahman,Wagdi Saber Soliman,Sabri Salaheldin 한국원예학회 2021 Horticulture, Environment, and Biotechnology Vol.62 No.6
Nanoparticles are one of the most widely studied materials in this century, and they have important uses in various fi elds,including agriculture. Bio-stimulants play a vital role in the sustainable development of horticultural crops. The aim of thisstudy was to assess the eff ect of nano zinc and bio-stimulants (salicylic acid, moringa extract, seaweed extract) on growth,yield, and quality of roselle plants. The experiment was conducted during 2018 and 2019 and was a completely randomizedsplit-plot design. Nano zinc oxide of 0, 5, 10, and 15 ppm was used as the main plot, and bio-stimulants were used as the subplot. The results showed that application of nano zinc led to signifi cant increases in growth, yield, photosynthetic pigments,as well as anthocyanin content associated with increased zinc content in leaves. The highest values of all traits occurredunder treatment of 10 ppm of nano zinc. Also, bio-stimulants showed positive eff ects on all traits, and the best results wereachieved under treatment with seaweed, followed by moringa extract. The correlation coeffi cients showed signifi cant positivecorrelations among calyxes yield and anthocyanin and zinc content as well as with other growth traits and photosyntheticpigments. These results highlighted the important role of nano zinc in improving the growth, yield, and quality of the roselleplant, as well as the positive eff ects of seaweed as a bioactive stimulant. Therefore, it is recommended to include nano zincand seaweed extract in fertilization programs for achieving a sustainable production system of such crops.
Phuoc Quy Phong Nguyen,A.T. Hoang,Abdel Rahman M. S Al-Tawaha 국제이네비해양경제학회 2018 International Journal of e-Navigation and Maritime Vol.9 No.1
Recently, Oil spill incidents from maritime activities and port operation have been causing the serious ocean environment pollution, these problems are said to be the negative effects on the natural environment, social economy, marine species, and human health. Due to the high costs of treating oil spills and oil slick in comparison with a low-income country like Vietnam, many incidents related to the oil spill and oil slick have not been thoroughly processed. Cellulose components from Vietnamese agricultural residues used to produce the absorbent materials are one of the most urgent issues and this is the research object of this work. In this study, two types of structural lengths of cellulose added into PU matrix foam are used to measure how much crude oil, fuel oil, diesel oil and kerosene can be absorbed. The absorbent materials are designed after adding cellulose with 5%, 15%, 25% of mass, respectively. The achieved results show that the oil absorption capacity of PU-cellulose implemented 5% cellulose with 500μm of cellulose structure length and 25% cellulose with 3000μm of cellulose structure length are highest for crude oil. These study results from this work provide a reasonable price for the protection of the marine environment in the strategies of recovery and treatment of oil spill and oil slick on the seawater surface.
MicroRNAs and Metastasis-related Gene Expression in Egyptian Breast Cancer Patients
Hafez, Mohamed M.,Hassan, Zeinab K.,Zekri, Abdel Rahman N.,Gaber, Ayman A.,Rejaie, Salem S. Al,Sayed-Ahmed, Mohamed M.,Shabanah, Othman Al Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.2
Aim and background: MicroRNAs (miRNAs) are a class of naturally occurring small noncoding RNAs that regulate gene expression, cell growth, differentiation and apoptosis by targeting mRNAs for translational repression or cleavage. The present study was conducted to study miRNAs in Egyptian breast cancer (BC) and their relation to metastasis, tumor invasion and apoptosis in addition to their association with the ER and PR statuses. Methods: Real Time RT-PCR was performed to identify the miRNA expression level of eight miRNAs and eight metastatic-related genes in 40 breast cancer samples and their adjacent non-neoplastic tissues. The expression levels of each miRNA relative to U6 RNA were determined using the $^{2-{\Delta}}CT$ method. Also, miRNA expression profiles of the BC and their corresponding ANT were evaluated. Results: The BC patients showed an up-regulation in miRNAs (mir-155, mir-10, mir-21 and mir-373) with an upregulation in MMP2, MMp9 and VEGF genes. We found down regulation in mir-17p, mir-126, mir-335, mir-30b and also TIMP3, TMP1 and PDCD4 genes in the cancer tissue compared to the adjacent non-neoplastic tissues. Mir -10b, mir -21, mir-155 and mir373 and the metastatic genes MMP2, MMP9 and VEGF were significantly associated with an increase in tumor size (P < 0.05). No significant difference was observed between any of the studied miRNAs regarding lymph node metastasis. Mir-21 was significantly over-expressed in ER-/PR-cases. Conclusion: Specific miRNAs (mir-10, mir-21, mir-155, mir-373, mir-30b, mir-126, mir-17p, mir-335) are associated with tumor metastasis and other clinical characteristics for BC, facilitating identification of individuals who are at risk.
Studies on Υ-irradiated polymer–nano calcined clay blended cement mortar composites
M.R. Ismail,E. Hamed,H.A. Abdel-Rahman,M.M. Younes,S.H. El-Hamouly 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.2
This study focuses on the preparation of blended cement mortars by a partial replacement of Portland cement by different ratios of nano-calcined clay. Also, the addition of PVA on blended cement mortar with different percentages. In addition to the influence of different doses of gamma rays on the physicochemical properties of the blended cement composites; the specimens are cured under tap water. Results showed that, compressive strength and bulk density of the composites increased with increasing the irradiation dose and PVA contents for certain values while, total porosity behaved in an opposite direction. XRD, SEM, TGA confirmed these conclusions.