Plague legacy

The Black Death, a bubonic plague that killed up to 50 percent of the people across North Africa, Europe, and Asia in the mid-1300s, played an important role in the evolution of the human immune system. A collaboration including UChicago professor of genetic medicine Luis Barreiro, published online October 19 in Nature, examined DNA from people who died before, during, and after the plague. In looking for immune-related gene variants that appeared less frequently after the pandemic, the researchers identified some that likely increased susceptibility to the pathogen, and thus died out along with victims of the plague. Those variants appearing more frequently after the plague revealed protective attributes passed down by survivors. One variant of the gene ERAP2 helps the immune system recognize infection, and medieval people with two copies would have been about 40 percent more likely to survive the plague. This gene, however, is associated with susceptibility to autoimmune diseases in modern populations, illustrating how pandemics can affect health for centuries.

Facebook accounts

A study published November 2 in the Proceedings of the National Academy of Sciences reveals that law enforcement Facebook accounts disproportionately post about crimes involving Black suspects. The study, coauthored by UChicago law professor John Rappaport, gathered all posts from almost 14,000 Facebook pages maintained by US law enforcement agencies and found that Black suspects were described in 32 percent of posts about crime that included a suspect’s race but represented only 20 percent of local arrestees. Facebook users were overexposed to posts about Black suspects across different crime types and geographical regions, and the rate of overexposure increased with the proportion of Republican voters and non-Black residents in the area. The study highlights the risk that biased reporting may reinforce stereotypes and influence crime policy.

Pseudo-privacy

Deidentification is a compromise between data science and privacy, but the most popular techniques are alarmingly easy to hack. When companies share data sets with researchers, for instance, the goal is to disguise identifying data—often just enough to satisfy legal requirements—while leaving enough information for analysis. The most common deidentification methods redact information that could be combined with other sources to reveal a person’s identity. In a study that received a Distinguished Paper Award at the 31st USENIX Security Symposium in August 2022, UChicago computer scientist Aloni Cohen focused on “downcoding,” a new kind of attack that reverse engineers deidentification and demonstrates the vulnerability of current methods. To demonstrate, Cohen combined data from LinkedIn and a massive open online course (MOOC) platform to identify students who had taken the class. This flaw could undermine the platform’s claims of compliance with the Family Educational Rights and Privacy Act—and shows that common forms of deidentification aren’t sufficient for true anonymity.

Reshaping tech

Electronics rely on conductive materials, with metals composing the largest group. About 50 years ago, scientists figured out how to make organic materials conduct electricity by introducing impurities. These materials are more flexible but aren’t very stable. What inorganic and organic conductors have in common is their orderly arrangement of atoms—that’s how electrons flow so easily through them. In a study published online October 26 in Nature, associate professor of chemistry John Anderson, SB’08, SM’08, and Jiaze Xie, SM’17, PhD’22, describe a new material that breaks the rules. By stringing organic and inorganic atoms together, the team created a substance that conducts electricity extremely well; is stable through temperature, humidity, and pH changes; and, most striking, is disorderly at the molecular level. Anderson describes it as “conductive Play-Doh.” The breakthrough can be used to design a new class of materials that are easy to shape, robust under everyday conditions—and could transform electronic technology.