Nasser A.M. Barakat

Electrospun Antimicrobial Polyurethane Nanofibers Containing Silver Nanoparticles for Biotechnological Applications

In this study, a new class of polyurethane (PU) nanofibers containing silver (Ag) nanoparticles (NPs) was synthesized by electrospinning. A simple method that did not depending on additional foreign chemicals was used to self synthesize the silver NPs in/on PU nanofibers. The synthesis of silver NPs was carried out by exploiting the reduction ability of N,N-dimethylformamide (DMF), which is used mainly to decompose silver nitrate to silver NPs. Typically, a sol-gel consisting of AgNO3/PU was electrospun and aged for one week. Silver NPs were created in/on PU nanofibers. SEM confirmed the well oriented nanofibers and good dispersion of pure silver NPs. TEM indicated that the Ag NPs were 5 to 20 nm in diameter. XRD demonstrated the good crystalline features of silver metal. The mechanical properties of the nanofiber mats showed improvement with increasing silver NPs content. The fixedness of the silver NPs obtained on PU nanofibers was examined by harsh successive washing of the as-prepared mats using a large amount of water. The results confirmed the good stability of the synthesized nanofiber mats. Two model organisms,E. coli andS. typhimurium, were used to check the antimicrobial influence of these nanofiber mats. Subsequently, antimicrobial tests indicated that the prepared nanofibers have a high bactericidal effect. Accordingly, these results highlight the potential use of these nanofiber mats as antimicrobial agents.

Potential Contribution of Retama raetam (Forssk.) Webb & Berthel as a Forage Shrub in Sinai, Egypt

The shortage of forage in arid areas is an important concern and it leads us to explore alternative options as nonconventional feed resources. Among potential forage species, samples of Retama raetam (R. raetam) were collected from six different locations representing four habitat types in two diverse phytogeographical regions in Egypt during the summer and winter seasons. Soil characteristics, growth performance, and nutritional traits of R. raetam were evaluated to assess the potential value of this legume as an alternative forage source in the Mediterranean ecosystem. Data showed that soil texture across the study sites had sandy, loamy, and clayey textures, whereas pH ranged from neutral to alkaline and organic carbon was low at all sites. Growth and production of R. raetam were significantly affected by seasonal variation in rainfall and, based on our study results, this effect was more important than specific site property variations such as soil texture and organic matter contents. Moreover, data indicate that R. raetam had wide ecological amplitude and growth performance as a function of site and season. Nutritional value of R. raetam was high enough to meet the nutrient requirements of several different grazing animals. Comparing the R. raetam nutritional value with those of the other wild plants, it can be concluded that R. raetam has strong potential as forage crop with valuable nutritional quality for browsing animals. Moreover, R. raetam may represent an alternative feedstuff to the conventional forage and a promising substitute fodder in Mediterranean ecosystem.