Advances

Advances gives a glimpse of the many significant research projects at the university. Tell us about your discoveries. E-mail: wisweek@news.wisc.edu.

Crystal growth yields more precise semiconductors
Sliced into almost paper-thin discs called wafers, semiconductors hold the circuitry that receives, transmits and processes information.

Traditionally, scientists “grow” quantities of single-crystalline semiconducting materials by immersing the tip of a pencil-shaped starter crystal, or “seed,” in a melt of the same composition. They then slowly withdraw and rotate the seed to form a thick rod shape. To make the crystal develop certain desired properties, they add special impurities to the melt before crystal growth. However, the resulting crystal’s composition and properties can vary along its length, so many parts built upon wafers from one crystal can be inconsistent in performance.

Materials Science and Engineering Professor Sindo Kou and graduate student Jia-Jie He have devised a method to ensure the melt composition stays constant. Scientists can apply this new method to crystals that are a mixture (an alloy) of two different semiconductors and grow them with a uniform composition. With a few modifications, users can adapt this technology easily to their existing equipment. Kou and He are patenting their discovery through the Wisconsin Alumni Research Foundation.

Old drugs could treat African sleeping sickness
By sorting through libraries of existing drugs, scientists have identified a subset of old medicines that may help combat a prevailing problem: the parasitic microbes that cause African Sleeping Sickness, a disease afflicting up to 500,000 people annually in sub-Saharan Africa and leaving more than 60 million at risk.

African Sleeping Sickness is a fatal disease transmitted by an infected tsetse fly. Drugs do exist to treat the disease, but many are too expensive or toxic to be truly effective.

“There’s a crushing need for new drug development,” says Jay Bangs, a microbiologist who helped scour the pharmacopia of old drugs with an eye toward new uses. “Rather than trying to make a drug from scratch,” Bangs explains, “we’ve gone to an existing databank of compounds and found a set that may be a new class of compounds for the treatment of African Sleeping Sickness.”

Bangs and his colleague Nigel Hooper identified a class of compounds — peptidomimetics. Bangs notes that the peptidomimetics would need to be rigorously tested in people infected with the sleeping sickness. However, he is optimistic: “We have lead compounds and have shown they have the potential to work. There’s a whole repertoire of similar compounds that can now be tested.”

Bangs and Hooper have applied for a “concept of usage” patent through the Wisconsin Alumni Research Foundation.

Corn yields useful product
An industrial chemical found in antifreeze, de-icing fluids and liquid detergents could soon stand alongside animal feeds, sweeteners and cooking oil as a commercial product made from corn. Randy Cortright and James Dumesic, chemical engineers, have invented a catalytic process for converting the corn-derived compound, lactic acid, into the chemical polypropylene glycol. More than 450 tons of polypropylene glycol are used in the United States annually. Unlike current processes for manufacturing polypropylene glycol, which make use of petroleum-based starting materials, this advance taps into a low cost, renewable resource available in surplus right now. The U.S. Department of Agriculture estimates that more than a billion bushels of corn went unused last year.