THE CHEMICAL WORLD THIS WEEK
Astrel 360 has high heat deflection temperature 264 P . s .i.
uses tubular coils and a pump for moving the blood through them, is the most efficient. Even so, a full treatment takes about six hours, and operating costs run up to $10,000 or more per year. The Kiil kidney, a membrane device, operates without a pump, reducing destruction of blood elements. It is cheaper than the Kolff unit, but also less efficient. Another potentially low-cost artificial kidney is one under development at Argonne National Laboratory (C&EN, July 14, page 10). The device uses epoxy resins to secure cellophane tubes to a manifold. The tubes are supported along their length by a meshed membrane inside each tube.
SEWAGE:
Algae at Work strength of the plastic is even better: 18,000 p.s.i. at 100° F. and 8000 p.s.i. at 500° F. Potential direct applications of Astrel in the chemical process industries are for such things as pipe, valves, valve seats, and seals. Current research at 3M's St. Paul, Minn., laboratories is centered on developing an optically transparent grade of Astrel. The markets 3M has in view for this grade are aircraft canopies and windshields. The advantages of the thermoplastic over metals and ceramics are in weight and fabrication costs, Mr. Cove says. Processing economics are among Astrel's advantages over thermosetting plastics. As with other thermoplastics, Astrel can be injection molded, a process that is automated and faster than the transfer or compression molding that must be used by most thermosetting plastics. Also, scrap thermoplastic can be remelted and re-used. One of the first commercial uses of Astrel is for electrical connectors in the SST. Amphenol Corp., part of Essex International, says it was able to meet the design criteria for the SST contract because of Astrel.
MEDICINE:
Dow's Tiny Kidney Ready "Highly successful" is how Dow Chemical terms continuing clinical testing of its small artificial kidney. Apparently so. The company has now entered into negotiations with Cordis Corp., Miami, Fla., toward the possibility of forming a joint company to make and market the kidney. Cordis manufactures medical instruments. Dow began clinical testing of the kidney almost exactly two years ago. 12 C&EN SEPT. 1, 1969
Since then, the kidney has been used and studied in about 80 chronic hemodialysis cases, involving some 3000 dialyses. Much of the work was carried out at San Francisco General Hospital. Big advantage of the kidney, which is about the size of a two-cell flashlight, is its potential for reducing considerably the cost of artificial kidney treatment. How much it might reduce the cost, however, isn't known yet. Dow hasn't made any official cost estimates, pointing out that this is an area that will have to be studied. The kidney is made with hollow, hair-sized cellulose fibers—up to 10,000 of them. The fibers, slightly larger than the capillary vessels of the human vascular system, were developed at Dow's Walnut Creek, Calif., laboratories. Clinical testing, Dowsays, has resulted in improvements in fiber geometry and in header geometry. Dowr points out that the kidney can be used with most of the common dialysate systems. The dialyzer itself is only part of a total system, and pumps, for example, are required for flushing saline solution through the unit. Normal blood pressure, however, is used to pump blood through the new device. Part of the research on the new kidney has, for the past several years, been funded by the National Institutes of Health. The company has also been working through the Food and Drug Administration. An artificial kidney that is cheaper and easier to operate than currently used units would be welcomed by hospitals and patients. Those now in use are large and difficult to operate and, thus, must be used mostly in hospitals. The Kolff kidney, which
Taking their cue from the successful use of bacteria to rid sewage of biodegradable wastes, engineers at the University of Kansas and Trans Union Corp. have a process that uses algae to remove inorganic nitrogen, phosphorus, and carbon compounds from secondary treatment plant effluent. Though it has long been known that algae feed on inorganic wastes, the phenomenon had not been thought to hold much promise for sewage treatment. For unlike bacteria, which flocculate and settle out in activated sludge secondary water treatment, algae remain dispersed and are discharged with the effluent into streams and lakes where they die, release inorganic nutrients, and form the slime that has come to characterize conditions in Lake Erie and other severely polluted bodies of water. Dr. Ross E. McKinney, working under the sponsorship of Trans Union at the University of Kansas, has solved the problem of algae's tendency to disperse by determining the conditions under which algae—like bacteriawill flocculate and settle out. Simply put, algae flocculation depends on the balance of algae to inorganic nutrients and maintenance of a minimum total solids concentration of at least 1000 mg. per liter, 50% of which must be algae. When nutrient levels are low enough in effect to "starve" the algae, their vitality is decreased. With this controlled, lowlevel vitality and the minimum 1000 mg. per liter concentration, Dr. McKinney says, the mean free path of the algae is decreased such that "the number of collisions between individual algae cells is greatly increased, while at the same time the ability of the algae cells to separate from each other is greatly decreased."
PERU:
Laboratory tests show sewage treatment process's feasibility
Day
Dry weight of solids in treatment tank (mg. per liter)
Dry weight of solids in effluent (mg. per liter)
Reduction of inorganic (per cent)
Reduction of phosphate (per cent)
2000 1300 1900
15 60 35 20 40
45% 85 65 65 15
52% 52 30 46 46
8 13 15 21 23
3550 1850
When the nutrient/algae ratio is too high, the algae gorge themselves and have enough energy to break away from each other by overcoming the van der Waals forces. Dr. McKinney has received U.S. Patent 3,462,360 covering his invention and Trans Union is offering the process for licensing. As the patent describes the process, equipment needs are simple and consist largely of a flat baffled tank where the incoming sewage is mixed with algae by a paddle wheel while the tank is irradiated by either sunlight or artificial lighting. The flocculated algae are then drawn off into a conical settling tank. Algae are recirculated until a maximum concentration of about 8000 mg. per liter is reached. Higher algae levels preclude drawing off a clear effluent from the settling tank. Algae may also be drawn off if sewage nutrient levels are too low to maintain the population. In either case, Trans Union says, recovered algae can be used as fertilizer or processed as a high-protein animal food.
GERONTOLOGY:
Antioxidants Slow Aging Antioxidants now approved for food use may retard aging processes in mammalian cells, said Dr. Alex Comfort of University College, London. He was speaking at the Eighth International Congress of Gerontology in Washington, D.C. Butylated hydroxytoluenes and ethoxyquine are among the aromatic phenols and amines whose use gives 40% increases in life spans of mice, he said. However, Dr. Comfort cautions against accepting these findings as evidence of prevention of aging. Restricting food intake produces similar lengthening of life in mice. The antioxidants may simply function by decreasing appetite or intestinal absorption. Statistically controlled feeding studies are needed to isolate the effect of antioxidants on mouse longevity.
Speaking about aging processes, Dr. Comfort points to the fact that plant cells seem to be able to go on dividing indefinitely, and it is possible to grow a whole tree from a single cell. Mammalian cells in cultures, however, seem to be capable of undergoing only the same number of divisions that they would have undergone in the body. Aging of mammalian cells seems to be linked to loss of information from the DNA-RNA synthetase-protein sequence, he says. The fact that aging of young cells can be induced by introduction of cytoplasm from aged ones indicates that the information loss is in the RNA synthetase rather than in the DNA in the nucleus as has been supposed. As RNA synthetase alters slowly with time, the RNA produced changes. The protein produced from the RNA then changes as amino acids are misspecified. When proteins are sufficiently different from normal sequences synthesized by young cells, they may be recognized as foreign by antibodies, which then give immune reactions. Dr. Comfort correlates this with the steep rise in RNA synthetase production in animals approaching death. When more and more of what is produced is defective, he says, you have to produce more to get enough that is correct. This suggests that antioxidants and free radical scavengers fed to animals throughout their lives may retard the reactions that damage RNA synthetase. Dr. Comfort sees the wide prevalence of antioxidants in foods as an actual barrier to clinical testing in humans. The dose of antioxidant used in experiments on mice was 1% by weight of the entire diet, whereas the Food and Drug Administration allows only 0.1% of antioxidant preservatives in foods. With such a large dose, sensitization is a danger. "A person might become sensitized to these things and there would be so many proprietary foods he couldn't eat," Dr. Comfort says. "He wouldn't thank you for that."
Turnaround for Grace W. R. Grace lost its chemical and paper operations in Peru for a few days and it took a resolution from the Peruvian government to straighten out what was almost an international incident. If Grace was in a skirmish with Peruvian bureaucracy, Standard Oil (N.J.) subsidiary International Petroleum Co. was in a pitched battle. Grace, though losing its sugar plantations, has been assured that its plants manufacturing plastics, paper, and alcohol will not be seized in a government resolution "modifying and rectifying" its Aug. 18 order that led to takeover of the entire W. R. Grace structure in Peru. International Petroleum Co., on the other hand, is being presented with a bill for $620 million and loss of its oil and distribution properties for the alleged illegal extraction of oil from Peru over the past 40 years. The Peruvian government, under president Juan Velasco, has embarked on one of the most ambitious land reform programs in South American history. The directions being taken will affect all facets of the country's economic and political life. U.S. firms are watching developments in Peru closely since reforms there may well serve as a model for changes in other South American nations. President Velasco has surrounded himself with a group of young military officers skilled in economics and modem management techniques. Their agrarian reform act seizes all land holdings and redistributes the land to the peasants. W. R. Grace was to have lost two sugar plantations. The company values the properties at $10 million, but it says that the plantations are losing money in 1969. The latest problem grew out of the fact that Grace operated all of its Peruvian ventures through a central administration. When the sugar operations couldn't be readily split out, the government took over the entire complex, including the manufacturing facilities (which are exempt from the land reform decree ). Peru now says that it is withdrawing its officials from the industrial operations. While Peru tries to create a middle class in one stroke, it must also continue to attract needed foreign capital and technology. If the land reform is accomplished without a serious loss in productivity, Peru can maintain a sound economy and a favorable balance of trade. As an executive for a chemical firm with plants in Peru points out, "If Velasco achieves these aims, opportunities for future private investment in manufacturing will be good." SEPT. 1, 1969 C&EN 13
