Into Thin Air
Helium prices have doubled in the past five years. The high demand is not exactly coming from people with party balloons to fill. Rather helium cools the superconducting coils of magnetic resonance imaging (MRI) devices, and the sale of those machines has grown tremendously, driving the demand for helium up by 25 percent since 2003. In contrast, helium production has increased by only about half as much.

In 2006 the U.S. sold 23,000 metric tons of helium, which filled 71 percent of the world’s helium needs (Algeria and Russia supplied most of the rest). At least one third of the U.S.’s contribution came from the federal helium reserve. Started in 1961, when helium was considered to be a crucial military and technological resource, the stock­pile had grown by 1996 to 170,000 metric tons, stored mostly in porous rock beds in the Cliffside gas field near Amarillo, Tex. As part of an effort to privatize government programs, a 1996 act mandated the sale of all but 2,900 tons by 2015. As a result, according to a 2000 National Academy of Sciences report, the total U.S. helium resources will disappear by 2035—probably sooner, because of rising demand. “If within the next five years, new sources of helium are not brought to market, there will be a helium shortage” if demand continues to grow at current rates, says Joseph Peterson of the Bureau of Land Management, the agency that manages the reserve. Recycling of this rare and nonrenewable resource may need to improve greatly to prevent shortfalls. —Sourish Basu

Forget the Storm
Researchers have hypothesized that taming the symptoms might boost survival odds during an influenza outbreak. Infections set off the release of cytokines, which are proteins that trigger inflammatory responses, including a rush of lymphocytes and the sacrifice of virus-compromised cells. The cytokine response to the avian flu virus, H5N1, is particularly vociferous, and some thought that this “cytokine storm” might be the main cause of death. Preventing it, unfortunately, does not appear to increase survival. Mice genetically engineered not to produce a key cytokine (TNF-alpha) fared no better than normal mice during infections. The same was true for ordinary mice given drugs to suppress cytokines. The findings, in the July 24 Proceedings of the National Academy of Sciences
USA, suggest that therapies should target the virus itself.

Choking on Mars
The Mars rovers Opportunity and Spirit seem to have weathered their biggest challenge yet—the weather. Throughout July especially, intense dust storms blocked sunlight from reaching their solar panels, causing severe power losses. At one point, Opportunity’s energy production dipped to 128 watt-hours from a normal average of 700. Without enough juice, the onboard electronics could have frozen over, permanently disabling the craft. By mid-August the storms had abated enough to permit the machines to fully recharge their batteries. Considering the robotic explorers’ remarkable toughness, they might be around to welcome the Phoenix lander. On August 4, NASA launched this craft, which will touch down on Mars on May 25, 2008. Its goal is to search for water on the planet’s northern plains.

New HIV Fighter
In August, Pfizer got the go-ahead to sell Selzentry (maraviroc). The anti-HIV compound is the first of a class that works by blocking the CCR5 receptor, a primary portal through which the virus enters cells. The drug results from studies of people who have a resistance against HIV because they make mutated versions of CCR5 [see “In Search of AIDS-Resistance Genes”; SciAm, September 1997]. Perhaps up to 60 percent of HIV-positive people have the form of the AIDS virus that enters cells through CCR5.

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