In chemistry, Salimuzzaman Siddiqui was the first Pakistani scientist to bring the therapeutic constituents of the neem tree to the attention of natural products chemists. Pakistani neurosurgeon Ayub Ommaya invented the Ommaya reservoir, a system for treatment of brain tumours and other brain conditions. Scientific research and development play a pivotal role in Pakistani universities, government- sponsored national laboratories, science parks, and the industry. Abdul Qadeer Khan, regarded as the founder of the HEU-based gas-centrifuge uranium enrichment program for Pakistan's integrated atomic bomb project. He founded and established the Kahuta Research Laboratories (KRL) in 1976, serving as both its senior scientist and the Director-General until his retirement in 2001, and he was an early and vital figure in other science projects. Apart from participating in Pakistan's atomic bomb project, he made major contributions in molecular morphology, physical martensite, and its integrated applications in condensed and material physics.