By Marcus Woo

Safer plastics

Without a chemical called a plasticizer, PVC—the third most commonly used plastic—remains brittle. To make commercial-grade plastics, PVC is typically pulverized and then melted together with plasticizers. But over time, the plasticizer can leach out—a problem because many plasticizers are phthalates, chemicals the body can mistake for hormones. Research has shown potential worrisome associations between phthalates and disorders such as reproductive abnormalities, cancer, and obesity.

“It’s a huge problem worldwide, both for humans and other species,” said Rebecca Braslau, professor of chemistry and biochemistry.

Her solution is to chemically bind the plasticizer onto the polymer chain of PVC, which prevents it from leaching out. Braslau has shown success with two phthalates whose chemical structure resembles tadpoles and frogs. More tests are needed, she says, but the biggest challenge might be getting industry on board.

Braslau R. Dialkylcarboxylate-aromatic-functionalized polymers that do not release endocrine disrupting compounds. U.S. Patent Application 20180155464, filed November 27, 2017, published June 7, 2018.

Full genome decoding

To fully understand a genome, you have to know how the whole thing fits together. One major research goal is to find genome assembly techniques—ways to reconstruct sequenced DNA—that are more accurate, cheaper, and faster.

“We have developed a method that makes it better on all those fronts,” said Ed Green, associate professor of biomolecular engineering.

With their technique, the researchers randomly slice up the genome and glue the pieces back together. Only segments that were originally close to each other are near enough to stick. Not only does this method identify neighboring sections, but it also reveals how far apart they are at all distance scales—something previous techniques couldn’t do.

Green RE, Lareau LF. Methods for genome assembly and haplotype phasing. U.S. Patent 10,089,437, filed January 31, 2014, issued October 2, 2018 (also U.S. Patents 9,411,930 and 9,910,955).

Power-saving clocking

In every computer processing unit, a component sends electrical signals that dictate how fast the chip runs—its clock speed.

“It’s the signal that synchronizes everything and makes it do computations,” said Matt Guthaus, professor of computer science and engineering. “It’s the heartbeat of the chip.”

Guthaus helped create a way for the chip to receive and interpret those signals using up to 90 percent less power. To achieve this, his approach detects the signals by measuring the flow of electricity through the wire (the current) instead of the amount of electricity (the voltage), as conventional chips do. Measuring the voltage requires draining the electricity—power that’s lost forever. The invention has the potential to greatly improve the performance of central and graphic processing units.

Guthaus M, Islam R. Current-mode clock distribution. U.S. Patent 10,097,168, filed September 11, 2017, issued October 9, 2018 (also U.S. Patent 9,787,293).

Efficient current conversion

The direct current (DC) from any power source must be converted to the alternating current (AC) used by most devices. But when that power source fluctuates—such as with solar power—the varying DC must first be converted to a steady one.

To bypass that step—and the extra circuitry and costs—Ricardo Sanfelice, professor of electrical and computer engineering, helped to create an algorithm that performs the conversion directly.

The algorithm is implemented on top of existing hardware. “The beauty is that it doesn’t change the architecture of standard conversion systems,” Sanfelice said.

Sanfilece RG, Chai J. Robust single-phase DC/AC inverter for highly varying DC voltages. U.S. Patent 9,876,442, filed October 9 2015, issued January 23, 2018.

Much needed antibiotics

Many disease-causing gram-negative bacteria like salmonella, shigella, yersinia (plague), and chlamydia share a common mechanism—called a type III secretion system (TTSS)—that hijacks host cells by inserting needle-like structures into them and injecting proteins that drive infection. Vicki Auerbuch Stone, associate professor of microbiology and environmental toxicology, and colleagues discovered several compounds (piericidin and a derivative) that can block TTSS function by preventing the needles from forming.

The compounds are toxic, however, so in their current form they don’t make useful drugs, Stone said. But studying how they work could lead to safer compounds, potential new antibiotics against which these important pathogens may be less likely to develop resistance.

“This is a first step to developing urgently needed new antibiotics that are effective against multi-drug resistant bacteria,” Stone said.

Stone VA, Linington RG, Wong WR, Duncan MC. Piericidin bacterial inhibitors. U.S. Patent 10,080,745, filed November 24, 2014, issued September 25, 2018.