Entity

Time filter

Source Type


Azeko S.T.,African University of Science and Technology | Azeko S.T.,Nigerian Turkish Nile University | Mustapha K.,African University of Science and Technology | Mustapha K.,Kwara State University | And 5 more authors.
Journal of Materials in Civil Engineering | Year: 2016

Polyethylene (PE) waste often piles up in the environment for up to 30 to 50 years, without complete degradation. This paper describes how PE waste can be used as a reinforcement in laterite bricks for sustainable building materials. The bricks are produced with different volume percentages (0-30 vol. %) of PE. The flexural/compressive strengths and fracture toughness values of the composite blocks are compared with those of mortar (produced from river sand and cement). The composite containing 20 vol. % of PE is shown to have the best combination of flexural/compressive strength and fracture toughness. The flexural/compressive strengths and fracture toughness values increase with increasing volume percentage of PE up to 20 vol. %, before decreasing to minimum values for composites with 30 vol.% of PE. The trends in the measured strengths and fracture toughness values are explained using composite and crack bridging models. © 2015 American Society of Civil Engineers. Source


Obayemi J.D.,African University of Science and Technology | Obayemi J.D.,Princeton University | Danyuo Y.,African University of Science and Technology | Danyuo Y.,Kwara State University | And 14 more authors.
Materials Science and Engineering C | Year: 2016

This paper presents the synthesis and physicochemical characterization of biodegradable poly (d,l-lactide-co-glycolide) (PLGA)-based microparticles that are loaded with bacterial-synthesized prodigiosin drug obtained from Serratia marcescens subsp. Marcescens bacteria for controlled anticancer drug delivery. The micron-sized particles were loaded with anticancer drugs [prodigiosin (PG) and paclitaxel (PTX) control] using a single-emulsion solvent evaporation technique. The encapsulation was done in the presence of PLGA (as a polymer matrix) and poly-(vinyl alcohol) (PVA) (as an emulsifier). The effects of processing conditions (on the particle size and morphology) are investigated along with the drug release kinetics and drug-loaded microparticle degradation kinetics. The localization and apoptosis induction by prodigiosin in breast cancer cells is also elucidated along with the reduction in cell viability due to prodigiosin release. The implication of this study is for the potential application of prodigiosin PLGA-loaded microparticles for controlled delivery of cancer drug and treatment to prevent the regrowth or locoregional recurrence, following surgical resection of triple negative breast tumor. © 2016 Elsevier B.V. All rights reserved. Source


Azeko S.T.,African University of Science and Technology | Azeko S.T.,Nigerian Turkish Nile University | Mustapha K.,African University of Science and Technology | Mustapha K.,Kwara State University | And 6 more authors.
Journal of Materials in Civil Engineering | Year: 2016

This paper presents the results of combined experimental and theoretical studies of the statistical distributions of the strength and fracture toughness of recycled polyethylene-reinforced laterite composites for potential applications in building materials. The composites are produced with different volume percentages (0-30% v/v) and particle sizes (~300±0.02, ~600 ± 0.03, ~900 ± 0.03, ~1,200±0.02, ~1,500±0.04, and 1,800±0.03 μm) of powdered polyethylene (PE) in a laterite matrix. The composites with ~900±0.03 μm and 20-volume percentage of PE are shown to have the best combination of flexural-compressive strengths and fracture toughness. The statistical variations in the flexural-compressive strengths and fracture toughness are well characterized by the Weibull distributions. © 2015 American Society of Civil Engineers. Source


Danyuo Y.,African University of Science and Technology | Danyuo Y.,Kwara State University | Dozie-Nwachukwu S.,African University of Science and Technology | Dozie-Nwachukwu S.,Biotechnology and Genetic Engineering Advanced Laboratory | And 12 more authors.
Materials Science and Engineering C | Year: 2016

We present the results of swelling experiments on poly(N-isopropylacrylamide) P(NIPA)-based hydrogels. The swelling characteristics of P(NIPA)-based homo-polymer and P(NIPA)-based co-polymers with Acrylamide (AM) and Butyl Methacrylate (BMA), were studied using weight gain experiments. The swelling due to the uptake of biosynthesized cancer drug, prodigiosin (PG), was compared to swelling in controlled environments (distilled water (DW), paclitaxel™ (PT) and bromophenol blue (BB)). PG was synthesized with Serratia marcescens (SM) subsp. marcescens bacteria. The mechanisms of drug diffusion and swelling of P(NIPA)-based hydrogels are also elucidated along with characterizing the heterogeneous porous structure of the P(NIPA)-based hydrogels. High Performance Liquefied Chromatography (HPLC) analysis revealed the purity of the biosynthesized prodigiosin to be 92.8%. PG was then absorbed by P(NIPA)-based hydrogels at temperatures between 28-48 °C. This is a temperature range that might be encountered during the implantation of biomedical devices for localized cancer treatment via drug delivery and hyperthermia. The results obtained are shown to provide insights for the design of implantable biomedical devices for the localized treatment of breast cancer. © 2015 Published by Elsevier B.V. Source


Danyuo Y.,African University of Science and Technology | Obayemi J.D.,African University of Science and Technology | Dozie-Nwachukwu S.,African University of Science and Technology | Ani C.J.,African University of Science and Technology | And 7 more authors.
Materials Science and Engineering C | Year: 2014

This paper presents an implantable encapsulated structure that can deliver localized heating (hyperthermia) and controlled concentrations of prodigiosin (a cancer drug) synthesized by bacteria (Serratia marcesce (subsp. marcescens)). Prototypical Poly-di-methyl-siloxane (PDMS) packages, containing well-controlled micro-channels and drug storage compartments, were fabricated along with a drug-storing polymer produced by free radical polymerization of Poly(N-isopropylacrylamide)(PNIPA) co-monomers of Acrylamide (AM) and Butyl-methacrylate (BMA). The mechanisms of drug diffusion of PNIPA-base gels were elucidated. Scanning Electron Microscopy (SEM) was also used to study the heterogeneous porous structure of the PNIPA-based gels. The release exponents, n, of the gels were found to between 0.5 and 0.7. This is in the range expected for Fickian (n = 0.5). Deviation from Fickian diffusion was also observed (n > 0.5) diffusion. The gel diffusion coefficients were shown to vary between 2.1 × 10- 12 m2/s and 4.8 × 10- 6 m2/s. The implications of the results are then discussed for the localized treatment of cancer via hyperthermia and the controlled delivery of prodigiosin from encapsulated PNIPA-based devices. © 2014 Elsevier B.V. Source

Discover hidden collaborations