Performance evaluation of microbial fuel cell using a radiation synthesized low density polyethylene-grafted-poly (glycidyl methacrylate-co-vinyl acetate) as a proton exchange membrane.

ABSTRACTThe present work focuses on the synthesis of a proton exchange membrane to be assembled in a microbial fuel cell (MFC) for simultaneous bioelectricity production and domestic wastewater treatment. The indigenous membrane was prepared by ionizing irradiation-induced graft copolymerization of glycidyl methacrylate (GMA) and vinyl acetate (VAc) onto low-density polyethylene and subsequently, the prepared grafted sheets were sulfonated via epoxy ring-opening of PGMA moieties. Parameters affecting the grafting degree were investigated and the prepared membranes were characterized by investigating their structural, thermal, mechanical, and electrical properties. Some physicochemical characteristics including ion exchange capacity, sulfonation density, and proton conductivity were also evaluated. The data confirmed the success of the preparation protocol to obtain a suitable membrane for the proposed application. Moreover, the performance of the assembled MFC was thoroughly investigated through the evaluation of its electrochemical behaviour including cyclic voltammetry, electrochemical impedance spectroscopy, columbic efficiency, and wastewater treatment capability. The sulfonated LDPE-g-P(GMA-co-VAc) membrane of 80% grafting degree shows substantial removal of chemical oxygen demand up to about 90% with columbic efficiency of 10.1%, columbic recovery of 8.7%, rate of energy harvest of 2.1 C/h and power density of 2.72 W m-2. However, the use of 10 mM of KMnO4 as electron acceptor drastically increase the harvested power density to reach 356.4 W m-2.

Radiation induced crosslinking of polyacrylamide incorporated low molecular weights natural polymers for possible use in the agricultural applications.

Superabsorbent hydrogels based on polyacrylamide (PAAm) and Na-alginate (Alg) or chitosan (CS) were synthesized by γ-rays. The effect of dose and copolymer composition on gel content and water absorbency of PAAm/Alg, PAAm/CS and PAAm/Alg/CS hydrogels were studied. The gel content and water absorbency follows the order PAAm/Alg>PAAm/Alg/CS>PAAm/CS. The effect of different cations, fertilizers, buffers on water absorbency of the hydrogels was investigated. Water retention capability of swollen hydrogels as a function of time was studied. PAAm/Alg hydrogel has a high water retention capability. An application of the prepared hydrogels in agricultural fields was performed using maize plants. The results showed that the presence of hydrogels had growth promotion effect on quality and quantity of maize plants. The plants treated by PAAm/Alg hydrogels showed 50% increase in the grain yield suggesting their possible use as a soil conditioner and a water reservoir for plant-soil system.

Predictors of Outcome of Living Donor Liver Transplantation for Hepatocellular Carcinoma.

The aim of this work is to study the different factors that affect the outcome of living donor liver transplantation for patients with hepatocellular carcinoma (HCC). Between April 2003 to November 2014, 62 patients with liver cirrhosis and HCC underwent living donor liver transplantation (LDLT) in the National Liver Institute, Menoufia University, Egypt. The preoperative, operative, and postoperative data were analyzed. After studying the pathology of explanted liver; 44 (71 %) patients were within the Milan criteria, and 18 (29 %) patients were beyond Milan; 13 (21.7 %) of patients beyond the Milan criteria were also beyond the University of California San Francisco criteria (UCSF) criteria. Preoperative ablative therapy for HCC was done in 22 patients (35.5 %), four patients had complete ablation with no residual tumor tissues. Microvascular invasion was present in ten patients (16 %) in histopathological study. Seven (11.3 %) patients had recurrent HCC post transplantation. The 1, 3, 5 years total survival was 88.7, 77.9, 67.2 %, respectively, while the tumor-free survival was 87.3, 82.5, 77.6 %, respectively. Expansion of selection criteria beyond Milan and UCSF had no increased risk effect on recurrence of HCC but had less survival rate than patients within the Milan criteria. Microvascular invasion was an independent risk factor for tumor recurrence.

Improvement of antioxidant activity of chitosan by chemical treatment and ionizing radiation.

Modification of chitosan (CS) to N-maleoylchitosan (NMCS), N-phthaloylchitosan (NPhCS) and sulfonated-chitosan (SCS) was done using maleic anhydride, phthalic anhydride and chlorosulfonic acid, respectively followed by exposing them to γ-rays at different doses. The molecular weights and structural changes of irradiated chitosan derivatives were determined by GPC, FT-IR and UV-vis spectrophotometer. The molecular weights decreased with increasing irradiation dose. Results revealed that the main polysaccharide structure remained after irradiation. To investigate the enhancement of antioxidant activity of chitosan and its derivatives of different molecular weights, radical mediated lipid peroxidation inhibition, scavenging effect of DPPH radicals, reducing power and ferrous ion chelating activity assays were used. Chitosan derivatives with different molecular weights exhibit antioxidant activity. The lower the molecular weights of chitosan and its derivatives, the higher the antioxidant activity. NMCS possessed high scavenging effect on DPPH radicals compared with NPhCS, SCS and ascorbic acid. The irradiated chitosan and its derivatives could be used as natural antioxidants.