Chemical world This WeeK to be a cure-all. Estimates of those who will be employed by the program run from 120,000 to 150,000, says the Labor Department's William Haltigan, but he pessimistically predicts that only several hundred openings will go to scientists and engineers. Meanwhile, other Administration programs for jobless scientists are meeting with some success. Out of 18,500 applicants to the Technology Mobilization Reemployment Program, 850 have jobs. Among 11,000 signed up for the National Registry of Unemployed Scientists and Engineers, there have been 2000 jobs. CRYOBIOLOGY:
Freezing blood cells The American Red Cross is beginning to put into large-scale use a process that its scientists have been perfecting for the past three years to preserve human red blood cells by freezing. The process, which is a modification of one developed by scientists at Boston's Chelsea Naval Hospital starting in 1960, will keep the red cells viable for years, if not indefinitely. By the end of this year, 18 Red Cross centers throughout the U.S. will be equipped to freeze, preserve, and thaw human red blood cells by the process. Two more centers will be added next year. By the end of 1972, these centers will be processing human red cells at an annual rate of about 100,000 units— the amount of red cells in a pint of whole blood. Storing frozen red cells has a number of major advantages. It permits the cells to be preserved for long periods, whereas such cells, when normally stored at 4° C, gradually deteriorate and usually are discarded after three weeks. An additional virtue of the freeze preservation method is that it eliminates the substances that can cause hepatitis. What specific step in this preservation technique destroys or eliminates the hepatitiscausing agents is not known, but is currently under study at the National Institutes of Health. The major drawback of using low-temperature preservation, however, is that the water in cells and tissues can freeze under these conditions. If ice forms inside a cell, the cell usually ruptures and dies as the ice expands. The problem, then, has been to find a substance (a cryoprotective 6
C&EN SEPT. 6, 1971
Facts & Figures The Sept. 6, 1971, issue of C&EN is produced in two parts—this regular edition and an extra one (mailed separately) called Facts & Figures, an annual staff compilation on the chemical and process industries.
agent) that, when added to the medium before it is chilled, will either prevent ice from forming or will reduce the ice formation to an acceptably low level. In the early 1950's, British scientists accidentally discovered that glycerol was such an agent. In the Red Cross method, red cells are first separated from almost all of the rest of the blood by centrifuging. The isolated red cells, containing small amounts of hard-to-remove contaminants, are then suspended in an aqueous saline solution containing 40% by weight of glycerol. The material is then chilled to - 8 5 ° C. and kept at this temperature for months or years—until the cells are needed. When needed, the material is thawed and then simultaneously centrifuged and thoroughly washed with saline solution to remove all of the glycerol and other foreign materials from the red cells. Finally, the cells are suspended in a saline solution containing glucose.
The subjects underwent hydrostatic pressures equivalent to depths between 100 and 1200 feet of sea water, in a helium-oxygen atmosphere. Nitrogen and crude neon were added and the effects studied. At 1200 feet, neon was used to simulate the density and physiological effects that helium would produce at 5000 feet. On the basis of these and other tests, Dr. R. W. Hamilton of Ocean Systems tells C&EN that crude neon may become the primary gas for diving between 150 and 1000 feet. The crude neon used in the tests (68 to 78% neon and 22 to 32% helium) is a by-product of production of oxygen and nitrogen from air, and is usually discarded. A diving mixture at 1000 feet might contain 72% neon, 24% helium, and 4% oxygen. Air cannot be used at depths greater than 150 feet because of nitrogen's narcotic effects. (Divers cite the "martini law": Every 50 feet of depth in nitrogen is equivalent to drinking one martini.) Neon's lower thermal conductivity and voice distortion, better decompression, and easier worldwide
OCEAN DIVING:
Breathing neon mixtures Divers exploring the ocean floor may in the future breathe neon gas mixtures. This prospect arises from results of the most comprehensive study yet of neon as a respirable gas, at the University of Pennsylvania's Institute for Environmental Medicine. Last Tuesday, four volunteers ended 24 days in a pressurized chamber simulating ocean depths. The extensive biomedical tests at Penn measured the effects on humans of breathing, at great depths and pressures, oxygen mixed with three inert gases—helium, nitrogen, and neon. The test staff includes scientists from Penn, Baylor University, NASA, U.S. Navy Bureau of Medicine and Surgery/ Office of Naval Research, Ocean Systems, Inc., Webb Associates, and the Canadian Institute of Environmental Medicine.
Diver undergoes respiratory tests
