Browsing by Author "Youssef, Ahmed M"

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    Influences of Ag-NPs doping chitosan/calcium silicate nanocomposites for optical and antibacterial activity
    (ELSEVIER SCIENCE BV, 2016-12) Youssef, Ahmed M; Abou Hammad, Ali B; Ali, Ahmed I; El-Nahrawy, Amany M
    Chitosan (CS)/calcium silicate nanocomposites pure and doped with Ag ions (1, 2 mol%) were prepared via sol gel method. The prepared CS/calcium silicate nanocomposites were investigated through X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The XRD results, indicating that after increasing the Ag ions in the CS/calcium silicate nanocomposite the crystallinity degree increased regularly in the prepared nanocomposites accompanying to the continuously rearrangement in the internal structure of nanocomposite under the effect of inorganic nanoparticles. Correspondingly, the optical properties of the prepared nanocomposites films were measured using UV/vis spectroscopy. The reflectance increased while the energy band gap decreased from 3.96 eV to 2.43 eV with Ag-ions concentration. More over the transition type changed from direct into indirect by adding Ag-ions, indicate that new band between valence and conduction band were formed. In addition, the optical parameters showed an increase in refractive indices and decrease in the surface and volume energies losses with increasing Ag-ions. Correspondingly, the prepared nanocomposites exhibited good antibacterial activity against gram positive (Staphylococcus aureus), gram negative (Pseudomonas aeruginosa) bacteria and fungi (Candidia albicans). The results suggested that the prepared CS/calcium silicate nanocomposites can be a promised candidate for optical sensors applications and smart packaging materials. (C) 2016 Elsevier B.V. All rights reserved.
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    Processed Cheeses Fortified by Laurus nobilis L. Extract Nanoemulsion Ameliorate Hyperhomocysteinemia in Ehrlich Ascites Carcinoma Model
    (NIDOC (Nat.Inform.Document.Centre), 2023-02) Hussein, Jihan; El- Bana, Mona A; Abdel Latif, Yasmin; El-sayed, Samah M; Youssef, Ahmed M; El-Naggar, Mehrez E; Medhat, Dalia
    We aimed to evaluate the protective effect of processed cheeses fortified by Laurus nobilis L. extract nanoemulsion against hyperhomocysteinemia in Ehrlich ascites carcinoma (EAC) model. Laurus nobilis L. extract nanoemulsion was prepared via spontaneous emulsification procedure. Then, nanoemulsion was added by different loadings to supplement processed cheeses. The morphology of Laurus nobilis L. extract nanoemulsion was detected using transmission electron microscopy (TEM). Female Swiss albino mice received processed cheese for two weeks then inoculated once with EAC cells. After the end of the experiment, blood samples were collected for determination of serum superoxide dismutase (SOD) , thiobarbituric acid reactive substances (TBARS), B-cell lymphoma 2 (Bcl-2), matrix metallopeptidase-9 (MMP-9), Tumor necrosis factor-α (TNF-α), and homocysteine (Hcy). Results revealed that the formation of Laurus nobilis L. extract nanoemulsion in spherical shape in size around 50 -120 nm. Mice inoculated with EAC cells showed significant increase in serum Hcy, TNF-α, TBARS, and MMP-9 levels while there was a significant decrease in SOD activity and Bcl-2 level. Pretreatment with different concentrations of Laurus nobilis L. extract significantly attenuated oxidative stress, inflammation, and induced apoptosis compared to EAC group.