Air pollution is a drag for renewable energy. Dust and other sky-darkening air pollutants slash solar energy production by 17 to 25 percent across parts of India, China and the Arabian Peninsula, a new study estimates. The haze can block sunlight from reaching solar panels. And if the particles land on a panel’s flat surface, they cut down on the area exposed to the sun. Dust can come from natural sources, but the other pollutants have human-made origins, including cars, factories and coal-fired power plants.

Scientists collected and analyzed dust and pollution particles from solar panels in India, then extrapolated to quantify the impact on solar energy output in all three locations. China, which generates more solar energy than any other country, is losing up to 11 gigawatts of power capacity due to air pollution, the researchers report in the Aug. 8 Environmental Science & Technology Letters. That’s a loss of about $10 billion per year in U.S. energy costs, says study coauthor Mike Bergin of Duke University. Regular cleaning of solar panels can help. Cleaning the air, however, is harder.

For certain HIV antibodies, having a buddy or two makes a big difference in the fight against the virus.

Combining the antibodies, called broadly neutralizing antibodies, may stop more strains of HIV than any single one can do alone, two new studies suggest. A “triple-threat” antibody molecule can bind to three different spots on the virus, researchers report online September 20 in Science. In Science Translational Medicine, a second team describes a cocktail of two single antibodies that each target a different region of the virus. Both methods prevented infection from multiple strains of an HIV-like virus in monkeys.
“We have known for many years that broadly neutralizing antibodies are extremely powerful antibodies,” says molecular biologist Nancy Haigwood of the Oregon Health & Science University in Portland, who was not involved in either study. Using more than one of these antibodies “is the most promising approach” to block HIV infection in humans because it offers more coverage, she says.

This extra coverage is needed because HIV is a master of mutation. “It’s really adopted every bit of what I would call molecular trickery to outwit our immune system, and it’s a constant battle,” says Gary Nabel, coauthor of the study in Science and chief scientific officer of Sanofi in Cambridge, Mass. The immune system keeps trying to recognize parts of the virus, but mutations in the virus can alter those sites. “You really want to have this broadside attack against the virus that hits multiple targets,” he says.

Broadly neutralizing antibodies are powerful because they can bind to multiple strains of HIV (SN: 8/19/17, p.7). The antibodies stop HIV from getting into cells to infect them. Still, “there is no single antibody” that can block all strains, says virologist Dan Barouch of Beth Israel Deaconess Medical Center in Boston.

Barouch and colleagues tackled the issue by mixing two of the antibodies together. The researchers divided 20 rhesus monkeys into four groups, giving one group the cocktail, two groups the individual antibodies and one group a saline solution with no antibodies. A day later, all of the monkeys were exposed to a mix of two simian-human immunodeficiency virus, or SHIV, strains. The outer protein that surrounds HIV, where antibodies bind, is the same in SHIV. None of the five animals that received the antibody cocktail became infected, while all of the other animals did, the researchers report in Science Translational Medicine.

Nabel and colleagues took a different tack: They developed a molecule that combines the binding talents of three antibodies into one. The researchers tested their “tri-specific” antibody in rhesus monkeys, giving eight animals the trio antibody while two other groups each received just one of the broadly neutralizing antibodies that inspired the molecule. The animals were exposed to a mix of SHIV strains five days later. Of the 16 monkeys in the solo antibody groups, 11 developed infections. None of the eight animals dosed with the trio antibody did.
Both teams’ antibody approaches “show impressive protection against a combination of viruses, suggesting that they would be effective” against diverse HIV strains in humans, Haigwood says.

Virologist David Margolis of the University of North Carolina School of Medicine in Chapel Hill notes that the approaches are most likely to have preventative potential, but they also may be therapeutic. The antibody combinations might “replace oral antiretroviral therapy, or stand in for oral therapy in medical situations where pills cannot be taken,” he says.

The next step for both methods is to test the combination antibodies in people, the authors say. Whether the strategy is most effective as a preventative measure, treatment or both, the papers suggest that “to achieve optimal protection in humans,” multiple antibodies or antibody targets are going to be needed, Barouch says.

A new eye on the variable sky just opened. The Zwicky Transient Facility, a robotic camera designed to rapidly scan the sky nightly for objects that move, flash or explode, took its first image on November 1.

The camera, mounted on a telescope at Caltech’s Palomar Observatory near San Diego, succeeds the Palomar Transient Factory. Between 2009 and 2017, the Palomar Transient Factory caught two separate supernovas hours after they exploded, one in 2011 (SN: 9/24/11, p. 5) and one earlier this year (SN: 2/13/17). It also found the longest-lasting supernova ever, from a star that seems to explode over and over (SN: 11/8/17).

The Zwicky survey will spot similar short-lived events and other cosmic blips, like stars being devoured by black holes (SN: 4/1/17, p. 5), as well as asteroids and comets. But Zwicky will work much faster than its predecessor: It will operate 10 times as fast, cover seven times as much of the sky in a single image and take 2.5 times as many exposures each night. Computers will search the images for any astronomical object that changes from one scan to the next.

The camera is named for Caltech astronomer Fritz Zwicky, who first used the term “supernova” in 1931 to describe the explosions that mark a star’s death (SN: 10/24/13).