Dose (megareps) 0 2320 2640
RESEARCH
Gel strength dynes/sq. cm. Paraffinic Aromatic 29,000 22,930 Solidified 4,510
T h e improved grease is still soft after the paraffinic oil grease has solidified. Study of radiation effects on colloidal lubricants may also lead to a better understanding of colloidal structures in general, the Cal Research group told the Symposium on Nuclear Technology in the Petroleum and Chemical Indus tries, jointly sponsored by the Divi sions of Petroleum Chemistry a n d I n dustrial and Engineering Chemistry at the Miami meeting.
More on Cancer & Tobacco Electron micrographs of t h e soap from a sodium stéarate ( 14% in naphthenic oil ) grease show effects of irradiation. Crystallites after 75 megareps ( right ) are encrusted with fine tubercles. These are whiter in t h e micrograph than t h e parent crystallites ( left ) and are more opaque to electrons, suggesting they are inorganic. Possible explanation: irradiation converts sodium ions in the soap to the metal; sodium migrates to the surface, reacts with moisture and CO » to form sodium carbonate—which would show u p as opaque tubercles
Safer cigarettes can be d e veloped, says Sloan-Kettering's W y n d e r , outlining a program for doing it JL H E RISK of lung cancer can b e re
Radiation-Resistant Greases N e w gelling agents a n d oils l e a d t o greases w i t h better r a d i a t i o n stability V J A M M A RADIATION severely
damages
the colloidal structure of lubricating greases made with conventional soap as gelling agents. Use of synthetic aromatics in place of these conventional agents has led to greases much more resistant to radiation. Kap.'d development of equipment for nuclear power has made these new radiation-resistant greases important. Valves, bearings, shackles, and other parts of such equipment requiring lubrication may b e heavily bombarded with radiation. T h e lubricants must retain desired qualities during and after such exposure if safe and efficient operation is to b e assured. • Mechanism of Damage. Radiation damages conventional greases in two stages, Bruce W . Hotten and J. G. Carrol, California Research Corp., explain. First, t h e grease softens during exposures up to 1000 megareps as soap crystallites disintegrate. Possible explanation: Metal and fatty acid ions discharge; metal migrates away from its normal site. Metallic and acidic fragments would then be too badly separated, and t h e acidic fragments possibly too oil-soluble to maintain a continuous crystallite network for strong gel structure. T h e probable change: 28
C&EN
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Then, greases harden at doses above about 1000 megareps as oil polymerizes and cross links. • Gelling Agent. The portion of conventional greases most sensitive to radiation is the gelling agent. This then is the obvious spot for first research attention in developing radiationresistant greases. T h e Cal Research workers find that a grease with sodium A T -octadecylterephthalamate as a gelling agent loses gel strength initially when irradiated in a Co 6 0 source b u t levels off at a medium gel strength at 400 to 800 megareps. Conventional stéarate grease, on the other hand, loses gel strength rapidly and liquefies at about 200 megareps. T h e irradiated terephthalamate crystallites change very little at these levels in electron micrographs. The Cal Research men also improve greases by using specially synthesized alkylaromatic oils. Two are octadecylα-methylnaphthalene and pentapropylene-a-methylnaphthalene. T h e first is more viscous and is less volatile. U n der irradiation, it compares with a paraffinic mineral oil—when each is gelled with 12% sodium N-octadecylterephthalamate—as follows:
duced by reducing the concentration of carcinogens in cigarette smoke, says Ernest L. Wynder. T h e Sloan-Kettering researcher, a pioneer exponent of the cigarettes-cause-iung-cancer idea, proposes four steps tn reduce that risk. Before the American Association for Cancer Research meeting in Chicago, he suggested: • Develop an effective filter. •* Remove t h e waxy coating from raw tobacco. • Reduce burning temperature of cigarette tobacco. • Moderate smoking habits. Reducing the amount of tobacco tar applied to animals reduces cancer: 10 grams of tobacco tar p e r year (maxi mum dose that does not kill the major ity of the animals) produces cancer in 409r. At one half t h e dose, cancer yields drop to one fourth; at one third the dose, no cancers result. These data, Wynder declares, parallel sta tistical findings in man. Wynder believes it is feasible to produce a filtered cigarette which would expose the smoker to 4 0 % less tar. If such a filter were placed on a regular size cigarette, t h e tar content could be reduced to a level which would significantly reduce cancer risk and produce safer cigarettes. T h e waxy coating of t h e tobacco leaf and stem is a major source of can cer-causing substances contained in whole tar, he says. Washing with a variety of solvents separates t h e wax. At the normal cigarette burning tem perature, this wax yields a tar of high
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It's like having extra help on t h e cleaning force when you put Atlantic U L T R A W E T S to work on factory and institutional clean-up jobs. U L T R A W E T 6 0 L is a s u p e r i o r liquid alkyl aryl sulfonate that works well in hot or cold water, hard or soft \vater. It increases the efficiency of floor scrubbing, heavy-duty liquids a n d hard surface cleaners as well as liquid sanitizers . . . emulsifies grease, speeds soil removal, keeps solids in uniform suspension and leaves n o soap scum. L e a d i n g c o m p o u n d e r s find t h a t U L T R A W E T 6 0 L provides uniform high quality and flexibility in t h e
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f o r m u l a t i o n of a l l - p u r p o s e l i q u i d cleaners. In scrub soap formulations it allows the use of a higher phosphate content with resulting clear solutions. F u r t h e r m o r e , it provides excellent controlled p H of alkalinity. T h e U L T R A W E T product advan tages a d d u p to sales advantages for you. Atlantic U L T R A W E T S are avail able in flake, bead and liquid form. F o r even greater economy, deliveries can be m a d e in bulk shipments. F o r m o r e information on o u r costcutting U L T R A W E T S , write, call or ware T h e Atlantic Refining Company at the nearest office listed.
mmtm PETROLEUM «JHfllWilH P h i l a d e l p h i a , Providence, C h a r l o t t e , C h i c a g o i n t h e West
L. H . B u t c h . - r C o .
In C a n a d a · Ν au g a tuck C h e m i c a l s D i v i s i o n of D o m i n i o n Rubber C o m p a n y , L t d . In Europe Atlantic C h e m i c a l s SAB, Antwerp, Belgium I n S o u t h A m e r i c a A t l a n t i c Rofin ing C o m p a n y of B r a z i l , R i o d e J a n e i r o
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φ Fallout Particles Pose for Portraits As part of its studies on devising effective protection against fallout from nuclear explosions, the Naval Radiological De fense Laboratory. San Francisco, analyzes fallout particles themselves. Particles, as seen through a pétrographie microscope, reveal: Tower shots at Nevada (left and center) produce particles that are mostly small, metallic-looking spheres. Many are magnetic. T h e spheres are colorless glass with an outside layer of black radioactive material.
cancer-producing activity: a 5'"' concentration painted on the backs of mice produces 27r< incidence of cancer within five months. In contrast, tar from whole tobacco leaf requires a 50' r solution applied for a year to yield a single cancer. According to Wynder, every one of the cancer-producing substances identified in whole tar is present, and in greater amounts, in tne t a r from waxy coating. W y n d e r also notes that tar from the waxy coating is less carcinogenic when burned at lower temperatures. Studies are now under way to test the cancercausing activity of cigarettes made from tobacco from which the waxy coating has been removed. George Wright and associates of University of Toronto carried out the chemical aspect of this work. • Rebuttal. Asked to comment about Wynder's report, the Tobacco Industry Research Committee says (in part): "Sweeping assumptions have been m a d e by attempting to relate some mouse skin painting experiments to selected statistics about human lung cancer t h a t have themselves been questioned b y other scientists. . . . Mention of 'safer cigarettes' is clearly based on a n u m b e r of assumptions that have not b e e n scientifically established and must still stand the test of careful scientific review." 30
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Silicates—feldspar and quartz in the Nevada soil—produce the glass. Radioactivity is concentrated in the iron-rich areas of the particles. Surface explosions at Nevada (cross section at right) throw out transparent, yellow-green spheres and irregular brown grains. The angular particles resemble the mineral grains mixed in the fireball. First shots of the particles were shown at the Naval Research Symposium, Washington, D. C , by NRDL's C. E. Adams.
Exploring Atherosclerosis Lipotropic preparations useless in treating atherosclerosis; despite claims made for such products J O - C A L L E D lipotropic factors that cause fat removal from tissue do not alter development of atherosclerosis when added to cholesterol-containing animal diets. According to Ruth Pick, Jeremiah Stamler, and Louis N. Katz of Michael Reese Hospital, various lipotropic factors have been tested to determine their possible action on atherosclerosis development in chicks. These include choline, inositol, pancreatin. activated whole pancreas, antifatty-liver factor, tocopherols, vitamin B1L>, lecithin, and others. The negative results obtained agree with those of most other workers studying other laboratory animals and man. Therefore, says Pick, there is no research basis to support the widely publicized claims that lipotropic preparations are useful in preventing and treating human atherosclerosis. Results with defatted brain extract preparations, as well as with plant sterols and other sterols closely resembling cholesterol, have been more en-
couraging. These materials, when fed to lab animals together with cholesterol, apparently prevent the gastrointestinal absorption of cholesterol, thus inhibiting atherosclerosis. However, recent studies indicate that some of these sterols may themselves be absorbed, with resulting atherogenesis. These substances must, therefore, still be considered experimental. Atherosclerosis is essentially a problem of cholesterol-lipide-lipoprotein metabolism in which nutrition plays a key role, she emphasizes. By alteration of cholesterol-lipide-lipoprotein metabolism, atherosclerosis can be induced in every one of the major laboratory animals. Atherosclerosis, however, is not exclusively a dietary disease, says Pick. In any large group of middle-aged Americans eating essentially similar diets, women have much less atherosclerosis. Among the men, a minority would exhibit clinical signs of coronary heart disease while a higher percentage would show coronary atherosclerosis if they were autopsied. Diet alone cannot account for such sex and individual differences. The problem of atherosclerosis apparently involves an intricate interplay between diet and individual differences in heredity, sex, physical activity, fatigue, stress, various metabolic diseases, local factors
