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Abdelrahman Awad,Isam H. Aljundi 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.8
A facilitated transport polyamide (PA) membrane was developed for gas separation by interfacial polymerization reaction of piperazine (PIP) and isophthaloyl chloride (IPC) supported on polysulfone (PSF) membrane previously prepared by dry/wet phase inversion method. The properties of the prepared membranes were characterized by SEM, FT-IR, TGA, and XRD. SEM images showed that a defect-free PSF, and rough PA membranes were fabricated, while the FT-IR spectra confirmed the formation of PA layer on top of the PSF support. The separation performance of the thin film PA and PSF membranes was evaluated using four gasses (CO2, CH4, N2, and O2). Compared to the PSF membrane, the PA membrane demonstrated an increased selectivity of CO2/CH4 and CO2/N2 by 178%, 169%, respectively. This improvement was attributed to the presence of amine functional groups, which acted as a fixed carrier to facilitate the transport of CO2 gas across the membrane. However, building the PA layer on top of PSF support reduced the membrane permeance of CO2 from 2.41 to 2.12 GPU as a result of the increased mass transfer resistance. Furthermore, the effect of operating temperature and pressure on the separation performance of the membranes was investigated.
Abdelrahman, Rashid Abdelbasit Saad International Journal of Computer ScienceNetwork S 2021 International journal of computer science and netw Vol.21 No.9
The research aims to identify the role of administrative leaders working in universities in the success of organizational development and change, and the extent of the relationship and ability of administrative leaders at all levels of leadership within universities to the effectiveness of the process of development and organizational change at Northern Border University. In addition to presenting some recommendations and suggestions that can contribute to identifying the best leadership styles that contribute to the success of the development process and positive organizational change. Where leadership, whether in the private sector or the public sector, is one of the main functions concerned with the processes of direction, development, and modernization in the performance of the facility and an important element to activate the organizations' ability to perform their role and achieve their goals. The behavior and trends of leaders represent an important indicator in knowing the type of efforts made by them to improve performance and develop organizations and human resources. The research reached many results, perhaps the most important of which is that the dominant leadership style in universities is the democratic style, followed by the bureaucratic leadership style. The results also showed that there is a significant role for administrative leaders in bringing about development and positive change at Northern Border University at the level of individuals, groups, and organizations. And it became clear that there is an availability of leadership capabilities to an acceptable degree in the administrative leaders. The results of the statistical analysis showed a positive relationship between administrative leadership ability and democratic style. In addition to the existence of a negative relationship between the administrative leadership ability and the bureaucratic style and the freestyle. It was also clear that there were no differences in dealing between males and females, as well as age, educational qualification, experience, and job grade, but there were differences in dealing with the job title.
Induction of P3NS1 Myeloma Cell Death and Cell Cycle Arrest by Simvastatin and/or γ-Radiation
Abdelrahman, Ibrahim Y,Helwa, Reham,Elkashef, Hausein,Hassan, Nagwa HA Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.16
The present study was conducted to investigate the effect of ${\gamma}$-radiation alone or combined with a cytotoxic drug, simvastatin, on viability and cell cycling of a myeloma cell line. P3NS1 myeloma cells were treated with the selected dose of simvastatin ($0.1{\mu}M/l$) 24 hours prior to ${\gamma}$-irradiation (0.25, 0.5 and 1Gy). The cell viability, induction of apoptosis, cell death, cell cycling, generation of ROS, and expression of P53, Bax, Bcl2, caspase3, PARP1 and Fas genes were estimated. The results indicated that simvastatin ($0.1{\mu}M/l$) treatment for 24 hours prior to ${\gamma}$-irradiation increased cell death to 37.5% as compared to 4.81% by radiation (0.5Gy) alone. It was found that simvastatin treatment before irradiation caused arrest of cells in G0/G1 and G2/M phases as assessed using flow cytometry. Interestingly, simvastatin treatment of P3NS1 cells increased the intracellular ROS production and decreased antioxidant enzyme activity with increased P53, Bax and Caspase3 gene expression while that of Bcl2 was decreased. Consequently, our results indicated that pre-treatment with simvastatin increased radio sensitivity of myeloma tumor cells in addition to apoptotic effects through an intrinsic mitochondrial pathway.
Abdelrahman Zkria,Fouad Abdel-Wahab,Yuki Katamune,Tsuyoshi Yoshitake 한국물리학회 2019 Current Applied Physics Vol.19 No.2
Ultrananocrystalline diamond/hydrogenated amorphous carbon composite films were deposited in the ambient of hydrogen by coaxial arc plasma deposition. The film compositions and chemical bonding structures were investigated by X-ray diffraction, X-ray photoemission and hydrogen forward scattering spectroscopies. The sp3 / (sp2 +sp3 ) ratio and hydrogen content in the film were estimated to be 64% and 35 at.%, respectively. The optical parameters and the optical dispersion profile were determined by using a variable angle spectroscopic ellipsometer at 55°, 65° and 75° angle of incidence in the photon energy range of 0.9–5 eV. Combinations of multiple Gaussian, and Tauc-Lorentz or Cody-Lorentz dispersion functions are used to reproduce the experimental data. Results of ellipsometry showed a refractive index of approximately 2.05 (at 2eV) and optical band gap of 1.63 eV. The imaginary part of dielectric function exhibited a peak at 3.8 eV, which has assigned to π-π* electron transitions. Furthermore, Electron spin resonance measurements implied the existence of dangling bonds, which might have a partial contribution to the optical absorption properties of the deposited films. A correlation between optical parameters and structural profile of the deposited films is discussed.
( Abdelrahman Saleh Zaky ),( Darren Greetham ),( Edward J. Louis ),( Greg A. Tucker ),( Chenyu Du ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.11
Yeasts that are present in marine environments have evolved to survive hostile environments that are characterized by high exogenous salt content, high concentrations of inhibitory compounds, and low soluble carbon and nitrogen levels. Therefore, yeasts isolated from marine environments could have interesting characteristics for industrial applications. However, the application of marine yeast in research or industry is currently very limited owing to the lack of a suitable isolation method. Current methods for isolation suffer from fungal interference and/or low number of yeast isolates. In this paper, an efficient and non-laborious isolation method has been developed and successfully isolated large numbers of yeasts without bacterial or fungal growth. The new method includes a three-cycle enrichment step followed by an isolation step and a confirmation step. Using this method, 116 marine yeast strains were isolated from 14 marine samples collected in the UK, Egypt, and the USA. These strains were further evaluated for the utilization of fermentable sugars (glucose, xylose, mannitol, and galactose) using a phenotypic microarray assay. Seventeen strains with higher sugar utilization capacity than the reference terrestrial yeast Saccharomyces cerevisiae NCYC 2592 were selected for identification by sequencing of the ITS and D1/D2 domains. These strains belonged to six species: S. cerevisiae, Candida tropicalis, Candida viswanathii, Wickerhamomyces anomalus, Candida glabrata, and Pichia kudriavzevii. The ability of these strains for improved sugar utilization using seawater-based media was confirmed and, therefore, they could potentially be utilized in fermentations using marine biomass in seawater media, particularly for the production of bioethanol and other biochemical products.
Negative Influence of the Hunger State on Rule-observance Behavior in Mice
Abdelrahman M. Alkahwaji,신희섭,이창준 한국뇌신경과학회 2023 Experimental Neurobiology Vol.32 No.1
Developing social strategies to share limited resources equally and maximize the long-term benefits of conflict resolution is critical for appropriate social interactions. During social interactions, social decision-making depends not only on the external environment, but also on internal factors, such as hunger, thirst, or fatigue. In particular, hunger, which is related to food as a physical need, plays a dominant role in social decision-making. However, the consequences of food deprivation on social decision-making are not well understood. We have previously shown that mice with rule-observance behavior are capable of resolving conflict during social decision-making by observing a well-established social strategy based on reward zone allocation. Here, we developed a rule-observance behavior paradigm wherein the hunger state is achieved by applying food restric- tions on mice prior to social behavior experiments.We found that the hunger state in mice deteriorated the established social strategy by decreasing reaction time, implying an increase in impulsivity. In contrast, the hunger state did not affect reward zone allocation, indicating no effect on spatial memory. This decrease in reaction time led to a significant increase in the percentage of violations during rule observance and a significant de- crease in the amount of reward (payoff equity). Our study proposes that the hunger state exerts a detrimental effect on appropriate social decision- making by decreasing reaction time, increasing violation, and decreasing payoff equity in rule-observance behavior.