American University in Cairo

About: American University in Cairo is a education organization based out in Cairo, Egypt. It is known for research contribution in the topics: Population & Context (language use). The organization has 2472 authors who have published 5339 publications receiving 73741 citations.

Green Synthesis of Platinum and Palladium Nanoparticles Using Peganum harmala L. Seed Alkaloids: Biological and Computational Studies.

Abstract: This study reports a facile and eco-friendly method for the green synthesis of platinum and palladium nanoparticles (Pt NPs and Pd NPs) using Peganum harmala seed alkaloid fraction. The ζ-potential of the synthesized Pt NPs, Pd NPs and Pt-Pd NPs were -11.2 ± 0.5, -9.7 ±1.2, and -12.7 ± 2.1 mV; respectively. Transmission electron microscopy (TEM) revealed the formation of spherical-shaped nanoparticles with smooth margins. The mean diameters of the synthesized Pt NPs, Pd NPs, and Pt-Pd NPs were determined using TEM analysis and were found to be 20.3 ± 1.9, 22.5 ± 5.7, and 33.5 ± 5.4 nm, respectively. The nanoparticles' bioreduction was confirmed by ultraviolet-visible (UV-vis) spectroscopy, X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy, and their organic contents were determined by thermal gravimetric analysis (TGA). The Pt-Pd NPs mixture showed more pronounced antioxidant activity of 843.0 ± 60 μM Trolox equivalent (TE)/mg NPs compared to the individual Pt NPs (277.3 ± 13.5 μM TE/mg NPs) and Pd NPs (167.6 ± 4.8 μM TE/mg NPs). Furthermore, the Pt-Pd NPs exhibited significant cytotoxic activities against lung cancer (A549) and breast adenocarcinoma (MCF-7) cells, IC50 of 8.8 and 3.6 µg/mL, respectively; as compared to Pt NPs (IC50 of 10.9 and 6.7 µg/mL, respectively) and Pd NPs (IC50 of 31 and 10.8 µg/mL, respectively and compared to carboplatin (IC50 of 23 and 9.5 µg/mL, respectively). Moreover, molecular docking studies were conducted to explore the possible anticancer and antioxidant mechanisms of the biogenic nanoparticles. Pt NPs, Pd NPs, and their mixture showed inhibitory activity against cysteine proteinase, which supports their high antitumor activity, but moderate antioxidant activity. In conclusion, Pd-Pt NPs mixture prepared using harmala seed alkaloid fraction showed potential as effective antineoplastic agents.

Preparation and evaluation of antioxidant packaging films made of polylactic acid containing thyme, rosemary, and oregano essential oils

Abstract: Τhyme, rosemary, and oregano essential oils (EOs) were incorporated into Polylactic acid resin (PLA) at a concentration of 10% (w/w) using the solvent casting method to generate antioxidant packaging films. Pure EOs showed a radical scavenging activity (RSA) ranging between 84.57% and 87.92% at 10,000 mg/L (ppm) using the 1,1‐Diphenyl‐2‐picrylhydrazyl radical (DPPH) method. The antioxidant activity of film methanolic extracts was 4%–6% lower than EOs at the same concentration. A significant reduction (p 0.05) permeation, migration, and percentage elongation at break of film properties. On the contrary, tensile strength, and Young's modulus significantly decreased (p < 0.05) in films containing EOs. PRACTICAL APPLICATIONS: The ability to prepare active packaging films that inhibit lipid oxidation and assist in shelf life extension of perishable foods is of great concern to the food industry and the research community. The incorporation of thyme, rosemary, and oregano EOs in PLA films resulted in the preparation of active packaging materials, as shown by: (i) the retardation of the lipid oxidation (ii) a considerable increase in the shelf‐life of the product. PLA films, enriched with EOs, may serve as alternative solutions to synthetic antioxidants for food preservation.

Generating Arabic text in multilingual speech-to-speech machine translation framework

Abstract: The interlingual approach to machine translation (MT) is used successfully in multilingual translation. It aims to achieve the translation task in two independent steps. First, meanings of the source-language sentences are represented in an intermediate language-independent (Interlingua) representation. Then, sentences of the target language are generated from those meaning representations. Arabic natural language processing in general is still underdeveloped and Arabic natural language generation (NLG) is even less developed. In particular, Arabic NLG from Interlinguas was only investigated using template-based approaches. Moreover, tools used for other languages are not easily adaptable to Arabic due to the language complexity at both the morphological and syntactic levels. In this paper, we describe a rule-based generation approach for task-oriented Interlingua-based spoken dialogue that transforms a relatively shallow semantic interlingual representation, called interchange format (IF), into Arabic text that corresponds to the intentions underlying the speaker's utterances. This approach addresses the handling of the problems of Arabic syntactic structure determination, and Arabic morphological and syntactic generation within the Interlingual MT approach. The generation approach is developed primarily within the framework of the NESPOLE! (NEgotiating through SPOken Language in E-commerce) multilingual speech-to-speech MT project. The IF-to-Arabic generator is implemented in SICStus Prolog. We conducted evaluation experiments using the input and output from the English analyzer that was developed by the NESPOLE! team at Carnegie Mellon University. The results of these experiments were promising and confirmed the ability of the rule-based approach in generating Arabic translation from the Interlingua taken from the travel and tourism domain.