NEWS OF THE WEEK

However, a spokesman for the Chica­go Board of Trade believes its recently approved spot and futures market for sulfur dioxide emissions allowances (C&EN, May 11, page 30) will offer fast­er trades than those arranged via con­sultants and private brokers, as well as provide immediate public price refer­ences. Trading at the Chicago Board of Trade may begin late this year or early in 1993 for allowances usable in 1995 and beyond.

Marc Reisch

Biological magnets found in human brain Microscopic crystals of the magnetic material magnetite (Fe304) have been isolated from samples of human brain tissue, a team of scientists at California Institute of Technology, Pasadena, an­nounced last week.

If it holds up, this controversial find­ing may help explain anomalous results that have been observed by researchers during magnetic resonance imaging (MRI) of the brain. It also opens the pos­sibility that magnetic fields associated with MRI and with some household ap­pliances might have biological effects.

The research was conducted by Jo­seph L. Kirschvink, an associate profes­sor of geobiology at Caltech; Atsuko Kobayashi-Kirschvink, an associate re­search engineer at Caltech; and Barbara J. Woodford, formerly a Caltech research fellow and now a research associate at the University of Southern California.

The work has been greeted with some skepticism. Kirschvink notes that Science, Nature, and the New England Journal of Medicine rejected, without review, a pa­per describing the team's results. How­ever, after review it has been accepted for publication soon in the Proceedings of the National Academy of Sciences.

Kirschvink points out that 'biological magnets have been found in a number of different living organisms, including mollusks, bacteria, honeybees, pigeons, and salmon." Scientists suspected mag­netic material might be found in human tissue, he adds, but convincing evidence has been difficult to obtain.

"A number of conflicting and contro­versial studies of the possible health ef­fects associated with electromagnetic fields have been published recently," he notes. "Many scientists dismissed out of

hand studies showing possible health ef­fects," thinking there are "no plausible mechanisms by which electromagnetic fields could affect biological tissue."

The group's research shows magnetite crystals in the human brain can be af­fected by magnetic fields only slightly stronger than Earth's magnetic field. However, he claims, electromagnetic fields associated with most power trans­mission lines—which some environ­mentalists claim are responsible for ad­verse health effects on people living near them—are not strong enough to affect the magnetite crystals isolated from hu­man brain tissue.

"It is possible that the presence of magnetite may mediate health effects of magnetic fields," Kirschvink says. "But in my opinion, the jury is definite­ly still out on whether electromagnetic fields actually do have health effects."

The Caltech team demonstrated the presence of magnetic material in brain tissue by two methods. In one, they used an extremely sensitive magnetometer to measure the total magnetic moment of ferromagnetic materials in tissue sam-

Allied-Signal has begun construction of a $220 million polyester industrial fiber plant in France, 150 miles northeast of Paris in Longlaville. In so doing, the firm not only is making its largest in­vestment ever outside the U.S., but also is going head-to-head in Europe with its principal U.S. polyester competi­tor—Hoechst.

Allied-Signal says the plant will open in late 1993, and will employ about 300 production workers. By the autumn of 1994, it is scheduled to reach full capaci­ty of 19,000 metric tons a year of polyes­ter, for use in car tires and other heavy-duty reinforcement applications. The plant will supply the European market with polyester fiber now shipped from the company's Moncure, N.C., plant, and give Allied-Signal's industrial fibers division a foothold in Europe.

The plant shows Allied-Signal's rec­ognition of the increasingly global na­ture of the fibers market. Just last month, Du Pont announced purchase of ICI's European nylon operations (C&EN, April 27, page 5).

Another reason for Allied-Signal's venture is what the firm sees as market opportunity: Polyester is now used in

pies. The magnetometer detects only such permanently magnetized particles within a solid sample; all other cellular iron and other diamagnetic or paramag­netic materials are invisible to it. This analysis revealed that all of the samples contained ferromagnetic material.

In the other method, the team used a powerful magnet and special test tubes to isolate two types of magnetite crystals from dissolved tissue samples. "I don't know whether people have a magnetic sense," Kirschvink says, "but many of the magnetite crystals we found in hu­man brains are very similar to those in bacteria." The crystals appear organized to be optimal for use as a magnet.

The analyses revealed all brain tissue has significant levels of magnetite— about 4 ng per gram of tissue. The high­est levels, 70 ng per gram of tissue, were found in the meninges, the membranes that cover the brain. This translates to about 5 million magnetite crystals per gram of tissue. The magnetometer stud­ies suggest these crystals occur in clumps of between 50 and 100 particles.

Rudy Baum

only 15% of European-produced tires, compared with 98% in North America and 83% in Japan. European tire man­ufacturers still use large quantities of rayon and nylon.

Allied-Signal is entering its largest competitor's home market even as it defends itself against a suit brought by Hoechst Celanese, Hoechst's U.S. affili­ate (C&EN, March 9, page 8). The suit alleges infringement of two of Hoechst Celanese's patents related to manufac­ture of high-performance polyester yarns used in radial tires. Allied-Signal says its polyester yarn products and processes do not violate Hoechst's pat­ents, and "our operation in France will not infringe either."

In addition to Hoechst, which claims to be the world's largest polyester indus­trial fiber manufacturer for tires and rub­ber mechanical goods, other European competitors include Akzo and the Visco-suisse operations of Rhône-Poulenc. In the U.S., Allied-Signal's competitors in­clude not only Hoechst Celanese, but also Bridgestone-Firestone and Akzo, which recently bought the Goodyear tire yarn operations.

Marc Reisch

Allied-Signal to make tire cord in France

6 MAY 18,1992 C&EN