A New Isolation and Evaluation Method for Marine-Derived Yeast spp. with Potential Applications in Industrial Biotechnology

( 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.

Solar light-active S-scheme TiO2/In2S3 heterojunction photocatalyst for organic pollutants degradation

Manjiri A. Mahadadalkar,Ganesh Dhakal,Sumanta Sahoo,Deivasigamani Ranjith Kumar,Marjorie Lara Baynosa,Van Quang Nguyen,Mostafa Saad Sayed,Abdelrahman M. Rabie,Woo Kyoung Kim,Jae-Jin Shim 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.124 No.-

Heterojunction TiO2/In2S3 composite photocatalyst was prepared using a simple low-temperature onestephydrothermal method. In2S3 nanosheets with a thickness of 1–5 nm were decorated with 20–30 nm TiO2 nanoparticles, forming a stable heterojunction. The electron transfer mechanism and bandalignment between TiO2 and In2S3 was studied using X-ray photoelectron spectroscopy and UV–visiblespectroscopy, which suggested the formation of an S-scheme heterojunction in TiO2/In2S3 composite. The TiO2/In2S3 composite with a 1:1 mole ratio showed 99.9% photocatalytic degradation ofRhodamine B within 20 minutes of solar light irradiation, which was better than the results for pristineTiO2, pristine In2S3, and their physical mixture, as well as any other previously reported materials of thesame kind. The as-prepared TiO2/In2S3 composite showed excellent stability (98% for Rhodamine B) evenafter five successive reuse cycles. This excellent performance of TiO2/In2S3 was attributed to the S-schemeheterojunction because of an internal electric field, columbic attraction, and band bending. A radical trappingstudy showed that superoxide radicals O2 contribute the most to the photocatalytic degradationof Rhodamine B followed by hydroxyl radicals (OH) and holes (hVB+ ). The use of a low synthesis temperatureand a simple, one-step formation method, with no secondary pollutants generated, makes this processan environmentally friendly and sustainable solution for cost-effective wastewater treatment,highlighting its future commercial applications.

Dynamic analysis of piezoelectric perforated cantilever bimorph energy harvester via finite element analysis

Yousef A. Alessi,Ibrahim Ali,Mashhour A. Alazwari,Khalid Almitani,Alaa A Abdelrahman,Mohamed A. Eltaher Techno-Press 2023 Advances in aircraft and spacecraft science Vol.10 No.2

This article presents a numerical analysis to investigate the natural frequencies and harmonic response of a perforated cantilever beam attached to two layers of piezoelectric materials by using the finite element method for the first time. The bimorph piezoelectric is composed of 3 layers; two of them at the outer are piezoelectric, and the inner isotropic material. A higher order 3-D 20-node solid element that exhibits quadratic displacement behavior is exploited to discretize the isotropic layer, and coupled piezoelectric 3D element with twenty nodes is used to mesh the top and bottom layers. CIRCU94 element is added to act as a resistor part of the model. The proposed model is validated with previous works. The numerical parametric studies are presented to illustrate the effects of perforation geometry, the number of rows, the resistance on the natural frequencies, frequency response, and power. It is found that the thickness has a positive relationship with the natural frequency. Perforations help in producing higher voltage, and the best shape is rectangular perforations, and to produce higher voltage, two rows of rectangular perforations should be applied.

Simulation of Earthquake Motion Phase considering Its Fractal and Auto-covariance Features

Adam A. Abdelrahman,Tadanobu Sato,Chunfeng Wan,Lei Zhao 대한토목학회 2019 KSCE Journal of Civil Engineering Vol.23 No.9

The earthquake motion phase (EMP) is decomposed into linear delay and fluctuation parts. In this paper, the peculiar stochastic characteristics of the fluctuation part of the phase (FPP) are discussed. First, we show that the FPP has self-affine similarity and should be expressed as a fractal stochastic process by using several observed earthquake motion time histories, as well as the FPP has a long term memory in the frequency domain. Moreover, the possibility of simulating FPP using the simple fractional Brownian motion (fBm) is discussed and conclude that this is not possible. To overcome this problem, we develop a new stochastic process, the modified fBm that is able to simulate a stochastically rigorous sample FPP. This newly developed algorithm represents the phase characteristics of the observed EMP well.

Fabrication of a three-dimensional bone marrow niche-like acute myeloid Leukemia disease model by an automated and controlled process using a robotic multicellular bioprinting system

Dana M. Alhattab,Ioannis Isaioglou,Salwa Alshehri,Zainab N. Khan,Hepi H. Susapto,Yanyan Li,Yara Marghani,Arwa A. Alghuneim,Rubén Díaz-Rúa,Sherin Abdelrahman,Shuroug AL-Bihani,Farid Ahmed,Raed I. Felim 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background Acute myeloid leukemia (AML) is a hematological malignancy that remains a therapeutic challenge due to the high incidence of disease relapse. To better understand resistance mechanisms and identify novel therapies, robust preclinical models mimicking the bone marrow (BM) microenvironment are needed. This study aimed to achieve an automated fabrication process of a three-dimensional (3D) AML disease model that recapitulates the 3D spatial structure of the BM microenvironment and applies to drug screening and investigational studies. Methods To build this model, we investigated a unique class of tetramer peptides with an innate ability to selfassemble into stable hydrogel. An automated robotic bioprinting process was established to fabricate a 3D BM (niche-like) multicellular AML disease model comprised of leukemia cells and the BM’s stromal and endothelial cellular fractions. In addition, monoculture and dual-culture models were also fabricated. Leukemia cell compatibility, functionalities (in vitro and in vivo), and drug assessment studies using our model were performed. In addition, RNAseq and gene expression analysis using TaqMan arrays were also performed on 3D cultured stromal cells and primary leukemia cells. Results The selected peptide hydrogel formed a highly porous network of nanofibers with mechanical properties similar to the BM extracellular matrix. The robotic bioprinter and the novel quadruple coaxial nozzle enabled the automated fabrication of a 3D BM niche-like AML disease model with controlled deposition of multiple cell types into the model. This model supported the viability and growth of primary leukemic, endothelial, and stromal cells and recapitulated cell-cell and cell-ECM interactions. In addition, AML cells in our model possessed quiescent characteristics with improved chemoresistance attributes, resembling more the native conditions as indicated by our in vivo results. Moreover, the whole transcriptome data demonstrated the effect of 3D culture on enhancing BM niche cell characteristics. We identified molecular pathways upregulated in AML cells in our 3D model that might contribute to AML drug resistance and disease relapse. Conclusions Our results demonstrate the importance of developing 3D biomimicry models that closely recapitulate the in vivo conditions to gain deeper insights into drug resistance mechanisms and novel therapy development. These models can also improve personalized medicine by testing patient-specific treatments.

Dynamic analysis of functionally graded (FG) nonlocal strain gradient nanobeams under thermo-magnetic fields and moving load

Alazwari, Mashhour A.,Esen, Ismail,Abdelrahman, Alaa A.,Abdraboh, Azza M.,Eltaher, Mohamed A. Techno-Press 2022 Advances in nano research Vol.12 No.3

Dynamic behavior of temperature-dependent Reddy functionally graded (RFG) nanobeam subjected to thermomagnetic effects under the action of moving point load is carried out in the present work. Both symmetric and sigmoid functionally graded material distributions throughout the beam thickness are considered. To consider the significance of strain-stress gradient field, a material length scale parameter (LSP) is introduced while the significance of nonlocal elastic stress field is considered by introducing a nonlocal parameter (NP). In the framework of the nonlocal strain gradient theory (NSGT), the dynamic equations of motion are derived through Hamilton's principle. Navier approach is employed to solve the resulting equations of motion of the functionally graded (FG) nanoscale beam. The developed model is verified and compared with the available previous results and good agreement is observed. Effects of through-thickness variation of FG material distribution, beam aspect ratio, temperature variation, and magnetic field as well as the size-dependent parameters on the dynamic behavior are investigated. Introduction of the magnetic effect creates a hardening effect; therefore, higher values of natural frequencies are obtained while smaller values of the transverse deflections are produced. The obtained results can be useful as reference solutions for future dynamic and control analysis of FG nanobeams reinforced nanocomposites under thermomagnetic effects.

Studying the effect of CO2 and catalyst preparation of supported V2O5/HMS on the oxidative dehydrogenation (ODH) of ethylbenzene

( Abdelrahman Rabie ),( A. M. Elfadly ),( M. A. Betiha ),박상언 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.0

The ODH of ethylbenzene to styrene was investigated over different loadings of V2O5 (5-30 wt.%) supported on HMS embedded with Zr. The all prepared materials were tested for their performance with environmentally friendly carbon dioxide as soft oxidant. All the prepared catalysts were treated by hydrothermal and microwave methods. The catalysts were characterized by XRD, IR, TPD, BET and TEM. With comparing the different loadings of the catalysts we found that the most active loading is 20% of V2O5/ZrO2-HMS microwave treated (V/ZHMSMW3). The catalyst V/ZHMS-MW3 exhibited higher activity among the all prepared catalysts. Maximum conversion of ethylbenzne 82.44, yield 82.19 and selectivity 99.75 for styrene were obtained by V/ZHMS-MW3.

Influence of flexoelectricity on bending of piezoelectric perforated FG composite nanobeam rested on elastic foundation

Ali Alnujaie,Alaa A. Abdelrahman,Abdulrahman M. Alanasari,Mohamed A Eltaher 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.49 No.4

A size dependent bending behavior of piezoelectrical flexoelectric layered perforated functionally graded (FG) composite nanobeam rested on an elastic foundation is investigated analytically. The composite beam is composed of regularly cutout FG core and two piezoelectric face sheets. The material characteristics is graded through the core thickness by power law function. Regular squared cutout perforation pattern is considered and closed forms of the equivalent stiffness parameters are derived. The modified nonlocal strain gradient elasticity theory is employed to incorporate the microstructure as well as nonlocality effects into governing equations. The Winkler as well as the Pasternak elastic foundation models are employed to simulate the substrate medium. The Hamiltonian approach is adopted to derive the governing equilibrium equation including piezoelectric and flexoelectric effects. Analytical solution methodology is developed to derive closed forms for the size dependent electromechanical as well as mechanical bending profiles. The model is verified by comparing the obtained results with the available corresponding results in the literature. To demonstrate the applicability of the developed procedure, parametric studies are performed to explore influences of gradation index, elastic medium parameters, flexoelectric and piezoelectric parameters, geometrical and peroration parameters, and material parameters on the size dependent bending behavior of piezoelectrically layered PFG nanobeams. Results obtained revealed the significant effects both the flexoelectric and piezoelectric parameters on the bending behavior of the piezoelectric composite nanobeams. These parameters could be controlled to improve the size dependent electromechanical as well as mechanical behaviors. The obtained results and the developed procedure are helpful for design and manufacturing of MEMS and NEMS.

Dynamic control of magnetically trapped indirect excitons using external magnetic bias: Transition from two- to one-dimensional lattice

Abdelrahman, A.,Ham, Byoung S. American Physical Society 2013 Physical review. B, Condensed matter and materials Vol.87 No.12

Spatially resolved inhomogeneous depressions of the excitons Zeeman splitting in an integrated magnetic-multiple quantum wells system

Abdelrahman, A.,Kang, H.,Yim, S. Y.,Vasiliev, M.,Alameh, K.,Lee, Y. T. American Institute of Physics 2011 JOURNAL OF APPLIED PHYSICS - Vol.110 No.1