"It was my first night as an intern and three children died before my eyes. I felt so helpless that I cried."
In 1996, Dr Mohammod Jobayer Chisti was working in the paediatric department of the Sylhet Medical College Hospital in Bangladesh. That evening he made a promise that he would do something to stop children dying from pneumonia.
About 920,000 babies and small children die from the disease each year, mostly in South Asia and Sub-Saharan Africa.
After two decades of research, Dr Chisti has now come up with a low-cost device with the potential to save thousands of babies' lives.