The engineers fashioned two coils into a helmet-like device that was fitted over the heads of the study participants.
As Morton H. Halperin, a McNamara deputy and one of the heads of the study, said in our film, the report was classified top secret because Mr. McNamara feared that President Lyndon B. Johnson would learn of the study and shut it down before it could be completed.
The study was permitted by the scientific research office in the School of Public Health, Fudan University, heads of the study hospitals, and directors of Obstetric and Gynaecology departments at the study sites.
But if results are promising, the study might expand to other hospitals, says Carol Tamminga, chair of the psychiatry department at UT Southwestern and head of the study.
"Once you shift the chemistry of the water, different species can survive in the area," said Robert A. Zampella, the ecology professor who was head of the study team.
"We just didn't come out with as strong a finding as everyone expected," said Dr. Marcia L. Stefanick, head of the study's steering committee.
The agency says it will probably pay the survivors' expenses to travel to its campus in Bethesda, Md. "This research looks at the natural history of anthrax infection," said Mary Wright, head of the study and chief of the biodefense clinical research branch at the infectious diseases institute.
The head of the study, Dr Dimitris Lagos, from the Cancer Research UK viral oncology group at University College London, said: "The viruses we tested have evolved with humans for millions of years and use a variety of biological tricks to establish life-long and mostly harmless infections.
The head of the study, demographer Robert Hogg of the B.C. Centre for Excellence in HIV/AIDS in Vancouver, Canada, says the analysis provides solid evidence that, where treatment is available, HIV is now a chronic disease.
The finding did not quite reach statistical significance, however, stressed the head of the study, epidemiologist Salim Abdool Karim of the Centre for the AIDS Programme of Research in Durban, South Africa.
The chief scientist, and head of the study, Mark Richardson, said BPA's impact was "so low as to be totally inconsequential".
