1. Department of Gastroenterology; Guys and St Thomas' NHS Foundation Trust; London; UK
2. Division of Gastroenterology and Hepatology; University Hospital Zurich; Zurich; Switzerland
3. Oesophageal Laboratory; Guys and St Thomas' NHS Foundation Trust; London; UK
4. RD Biomed Limited; Castle Hill Hospital; Hull; UK
5. Department of Biological Sciences and Bioengineering; Indian Institute of Technology; Kanpur; India
6. Physics and Applied Mathematics Unit; Indian Statistical Institute; Kolkata; India