Ibm Is Playing With A New Stack Of Chips

Instead of a circuit board in your next computer, look for a package the size of a sugar cube. On June 15, IBM inked an agreement to commercialize Irvine Sensors Corp.'s innovative packaging, which stacks more than 100 integrated circuits into a half-inch-high cube. Earlier this year, the tiny Costa Mesa (Calif.) company used its "cubing" technology to stack 80 memory chips to replace a PC's 40-megabyte hard-disk drive.

Such unusual packaging is needed to reduce a data processing bottleneck--the distance between chips on a circuit board. Irvine Sensors has spent 12 years and $30 million perfecting the cube for military and satellite uses.

While IBM cuts manufacturing costs, Irvine Sensors will develop a scaled-down cube for conventional packages, so computer makers can retrofit today's designs with extra memory. The technique will also work for credit-card-size memory technology recently introduced by American Telephone & Telegraph Co. and Intel Corp. to replace hard-disk drives.

Part 2

To your everyday beachgoer, snow doesn't come to mind in the quest for sunburn and skin-cancer protection. But scientists at Research Triangle Institute in North Carolina, have developed a special carbon dioxide "snow" that may help slow the thinning of the earth's ozone layer. This snow will replace ozone-depleting chlorofluorocarbons, or CFCs, which are currently used as solvents to clean microelectronic, aerospace, and optical equipment. Such industrial cleaning accounts for 20% of all CFCs used worldwide.

Computer chips and other surfaces sprayed with the CO2 snow appear to be as free from dust as those treated with the CFC solvent, says Liz Hill, an RTI chemical engineer. Furthermore, Hill says, the cost is comparable to treatment with CFCs, which must be phased out in the U.S. by 1995. Trying to solve the ozone problem with CO2, a contributor to global warming, may trouble some environmentalists. But RTI scientists say there will be no net increase in gaseous emissions since they use carbon dioxide that has already been created as a byproduct of other industrial processes.

Part 3

Long used in genetic research, fruit flies may soon help fight AIDS, hepatitis C, and cancer. Researchers at San Diego's Scripps Research Institute and Cytel Corp. in La Jolla, Calif., use the insects as factories to produce vaccines that help stimulate immune responses in patients afflicted with chronic diseases. The problem is that these people's white blood cells do not recognize and destroy diseased cells.

The researchers insert a gene into the flies, causing them to churn out special receptors that play a role in the human immune system. The scientists add virus or tumor cells to a test tube containing the extracted receptors, which, like settings for diamonds, lock onto portions of virus or tumor molecules. Then they incubate the mixture with a patient's white blood cells. After a few weeks of exposure to the virus-filled receptors, white blood cells will be charged up--and recognize and kill infected cells when injected back into the patient.

So far, the so-called ex vivo vaccines have succeeded in fighting tumors in mice. The company says human clinical trials for AIDS or melanoma are planned for early 1993.

Part 4

Cleaning the mess left over after the world's atomic-weapons binge is a slow process. But chemists have developed a new class of inorganic materials, called silico-titanates, that can help dispose of radioactive wastes. They can separate the highly radioactive material out of "radwaste" solutions, greatly reducing the volume that must be encapsulated in glass or ceramic for long-term disposal.

In tests on cesium 137, scientists at Texas A&M University and Sandia National Laboratories in Albuquerque found that silico-titanates are up to 60 times more efficient than materials currently used to immobilize high-level radwaste. The crystalline structure of the new material is chemically designed to be highly reactive with cesium ions, trapping them between layers of titanate.

Silico-titanates have also successfully trapped strontium 90, another radioactive isotope. Within two to three years, scientists hope to be able to extract all radioactive contaminants from weapons-production waste. The titanate material may also be useful in treating low-level radioactive waste, industrial chemicals such as nickel, and even groundwater.

Part 5

Glass bones seem about as practical as feet of clay. But researchers at the University of Dayton in Ohio say that glass fibers may soon replace metal pins in setting severely broken limbs. Currently, the patient undergoes a second operation to remove the metal pins. However, when special glass fiber implants are used, the body resorbs the glass as the bone mends.

Unlike ordinary glass, these fibers contain a blend of calcium, phosphorous, and tiny amounts of iron oxides. The combination makes the glass as strong as metal, yet allows the material to dissolve over time. Because they contain elements found in bone, the implants may even speed the recovery process by supplying calcium to the healing bone.

Preliminary studies suggest that the material is nontoxic, says Dayton researcher Binod Kumar. Glass fiber implants, he adds, should be cheaper than metal pins. Animal studies are under way, and human trials may start in about five years.