This research project would not have been possible without the support of many people. The author wishes to express her gratitude to her supervisor, Prof. Dr. XX who was abundantly helpful and offered invaluable assistance, support and guidance. Deepest gratitude are also due to the members of the supervisory committee, Assoc. Prof. Dr. YY and Dr. ZZ without whose knowledge and assistance this study would not have been successful. Special thanks also to all her graduate friends, especially group members; A, B, C, D and E for sharing the literature and invaluable assistance. Not forgetting to her best friends who always been there. The author would also like to convey thanks to the Ministry and Faculty for providing the financial means and laboratory facilities. The author wishes to express her love and gratitude to her beloved families; for their understanding & endless love, through the duration of her studies.