This research project was conducted to study the effects of irradiation on chitosan and its potential application as a plant growth promoter. Chitosan in the form of flakes was irradiated with gamma rays at irradiation dosage of 50 kGy, 100 kGy, 200 kGy and 400 kGy. The effect of irradiation on chitosan in terms of intrinsic viscosity and average molecular weight was measured using Ubbelohde capillary viscometry technique and the results obtained showed irradiation at doses of up to 50 kGy had caused an extremely significant reduction of both parameters and this trend continued at higher irradiation doses, although the decrease were not significant. The effect of various concentrations of chitosan and irradiated chitosan on growth promotion of Chinese kale (Brassica alboglabra) was hydroponically grown and cultivated for 50 days. Statistical analysis showed addition of 10 ppm of irradiated chitosan of 200 kGy and 400 kGy, respectively, resulted in an extremely significant increase in the percentage weight gain of Chinese kale (Brassica alboglabra). Results obtained in this study showed the potential use of irradiated chitosan as a plant growth promoter for plants grown hydroponically. � 2016 AIP Publishing LLC.

Dipalmitoylphosphatidylcholine (DPPC) is one of the most abundant lipids in the human body and carries out important physiological functions such as liver protection and fighting infections. This study was conducted to investigate the effect of ionising radiation on the chemical structure and surface characteristic of DPPC. Synthetic DPPC was dissolved in chloroform (1mg/ml) and irradiated with Cobalt-60 (dose range of 50 - 200 Gy). The change in surface characteristics due to gamma irradiation was determined by means of monolayer compression isotherms using a Langmuir trough. From the change in the isotherm features, the threshold dose that affected the surface characteristics of the DPPC monolayer was determined to be 60 Gy. With increasing dose value, the plateau feature in the DPPC isotherm became shorter and was shifted to higher surface pressures. Analysis using High Performance Liquid Chromatography (HPLC) and Mass Spectrometry (MS) suggested that gamma irradiation of DPPC destroyed the chemical structure of DPPC and produced two main radiolytic products, namely lisophosphatidylcholine, LPC (~495.3142 g/mol) and phosphatidic acid, PA (~718.916 g/mol) with an average percentage of LPC and PA of 23% and 74%, respectively.