The Chemical World This Week RESEARCH & TECHNOLOGY
OCTOBER
3,
1960
CONCENTRATES
• A key factor in the biosynthesis of 7-chlorotefracycline has been isolated by Dr, Philip A. Miller and co-workers at Lederle Laboratories. Called Cosynthetic Factor I, the crystalline compound is obtained from Streptomyces aureofaciens mutant W-5, which lacks the ability to make tetracyclines [JACS, 82, 5002, 5006, (I960)]. When W-5 is grown with mutant S-1308, which makes very little 7-chlorotetracycline but considerable 5a(lla)-dehydro derivative, S-1308 produces 2.8 grams of 7-chlorotetracycline per liter of culture vs. 0.2 gram per liter when grown alone. The active substance given off by W-5 (and most S. aureofaciens strains) is a catalyst rather than an intermediate, Lederle finds. One microgram is enough to stimulate formation of 50,000 micrograms of the chlorotetracycline. Early studies suggest that the compound may be a pteridin or flavin. • Silicon-nitrogen polymers are worth studying as possible high temperature materials, scientists at Southern Research Institute, Birmingham, Ala., conclude. Silazanes (nitrogen analogs of siloxanes) can be made in a variety of physical states, some with good thermal stabilities, says SRI's Dr. Robert E. Burks, Jr. Many siliconnitrogen compounds have been made in the past, he notes, but their importance has usually been discounted because the compounds hydrolyze easily. But increasing emphasis on high temperature polymers justifies studying this class of chemicals further. • Both cross-linking and intramolecular bridging are needed for wrinkle resistance in cellulosic fibers, according to a new theory by Dr. S. James O'Brien and W. J. van Loo, Jr., of American Cyanamid. In fact, only a small fraction of a cross-linking reagent actually cross-links the cellulose molecules. A larger fraction goes into some kind of intramolecular bridging, Dr. O'Brien told the Chemical Finishing Conference of the National Cotton Council held in Washington, D.C. • Nuclear gages can now be used to measure the flow of granular solids. Ohmart Corp., Cincinnati, Ohio, has developed a dry solids mass flow density gage, will install it in a cement plant within the next few weeks. Other materials which can be measured with the gage: plastics, foods, minerals, and others whose specific gravity
can be determined. The new gage uses a beta radiation source—strontium-90. Operation is based on the Bremstrahlung effect; a beta ray hitting a solid causes it to emit x-rays of various energies. These pass through the material to a conversion cell on the opposite side. The cell converts radiation directly to electrical current. ( For more on nuclear gages, see page 54. ) • A process for making honeycomb core out of plastic film has been developed by Hexcel Products, big honeycomb producer at Berkeley, Calif. Company won't describe the process, says only that the approach is entirely different from other honeycomb techniques. Polyethylene, polyvinyl chloride, polypropylene, and polycarbonate have already been used in the new process, and Hexcel says that theoretically any thermoplastic film can be used. With no immediate market in sight, work has not yet gone beyond the pilot stage. But Hexcel is banking on a wide range of physical, chemical, and mechanical properties to carry its product into profitable outlets. • West Germany will have a computer-controlled plant before the year is out. Badische Anilin- und Soda-Fabrik (BASF) will put a major chemical processing unit under computer control sometime in I960! The computer is Thompson . Ramo Wooldridge s RW-300, which is currently being used in several plants in the U.S. Specific process involved hasn't been revealed. The BASF installation will be at Ludwigshafen am Rhein, and will be the first closed-loop computer control system to be installed outside the U.S., Thompson Ramo Wooldridge says. )• The Ford Foundation breaks from previous custom with its new program to aid higher education: No restrictions are placed on how the , money should be used. Under the program, five private universities will get grants totaling $46 million. Schools to receive the grants are Stanford, $25 million; Johns Hopkins, $6 million; Notre Dame, $6 million; University of Denver, $5 million; and Vanderbilt, $4 million, As part of the program, the five universities agree to raise $117 million in matching funds. Stanford will come up with three dollars for every dollar of Foundation money. The four other schools promise to raise two dollars for every dollar received. OCT. 3, I96 0 C&EN
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