NEWS OF THE WEEK
CLAMPDOWN ON HFCs CLIMATE CHANGE: EPA rule
will bar more uses of the potent greenhouse gases
T
HE ENVIRONMENTAL PROTECTION AGENCY
is ratcheting back the allowed uses of hydrofluorocarbons (HFCs), commercial chemicals that are potent greenhouse gases. A new EPA regulation will limit the use of HFCs and blends containing HFCs in aerosols and blowing agents that expand plastic into foam and in refrigerants for vehicle air conditioners, coolers in retail stores, and vending machines. HFCs were developed to replace chemicals that deplete stratospheric ozone, such as chlorofluorocarbons. Although they don’t harm the ozone layer, many HFCs have high potential to contribute to global warming. EPA Administrator Gina McCarthy says the regulation will give a boost to chemical manufacturers that are selling more climatefriendly products. “This rule will not only MANDRITOIU/SHUTTERSTOCK
New refrigeration systems for supermarkets will be free of HFCs as of 2017, under EPA’s rule.
PROTEIN IN BLOOD LINKED TO AGING
ADAPTED FROM VILLEDA GROUP
NEUROSCIENCE: Increased levels of β2-microglobulin impair memory in mice
O Transfer of blood from old mice (top) to young ones, revealed molecules that could be involved in aging.
NE FRUSTRATING PART of getting older is
memory loss—forgetting where you put the TV remote, not remembering the name of the family that used to live next door. A new study in mice suggests that a protein that circulates in the blood and has levels that increase with age could be one culprit behind this mental decline. Finding ways to reduce the protein in the body could lead to therapies that prevent or reverse age-related memory loss, the researchers say. “It’s a very impressive paper and a major advance in our understanding of cognitive aging,” says Scott A. Small, a neurologist at Columbia University who was not involved in the study. The new work stems from a series of studies looking at molCEN.ACS.ORG
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reduce harmful greenhouse gas emissions but also encourage greater use and development of the next generation of safer HFC alternatives,” she says. Makers of alternative chemicals to HFCs are praising the regulation, anticipating higher demand for substances with lower global warming potential. “EPA’s action will accelerate the adoption of solutions with far less impact on the atmosphere while also spurring private-sector innovation and creating jobs,” says Ken Gayer, vice president and general manager of Honeywell’s fluorine products business. Honeywell is marketing hydrofluoroolefins as alternatives to HFCs. EPA says its rule, issued under the Clean Air Act, is focused on HFCs that have the highest global warming potential compared with alternative substances for the same end use. The regulation will cut U.S. emissions of greenhouse gases equivalent to 54 million to 64 million metric tons of carbon dioxide by 2025, the agency claims. Unveiled in early July, EPA’s rule will halt the use of HFC-134a as an air conditioner refrigerant in most cars and trucks starting with model-year 2021. The regulation also prohibits the use of certain HFCs as aerosol propellants, including HFC-227ea and blends containing it, HFC-125, and HFC-134a. EPA’s rule is a response to President Barack Obama’s 2013 Climate Action Plan, which in part called for the curbing of HFC emissions.—CHERYL HOGUE
ecules in blood associated with aging. Researchers, including Tony Wyss-Coray of Stanford University, have shown that transferring blood from young mice into old mice can reverse age-related loss in cognitive function. And the effect goes both ways: Blood from old mice can impair memory in young ones. Saul A. Villeda, a former postdoc in the Wyss-Coray lab and now a professor at the University of California, San Francisco, wanted to study a blood factor implicated in those previous studies as contributing to the aging process—β2-microglobulin (B2M). Scientists have known that this protein plays a role in pruning nerve cell connections in young, developing brains. In the new study, the researchers found that injecting B2M into the brains of young mice led to poor performance in tests of two types of memory compared with animals that didn’t receive the protein. But the effects weren’t permanent. If the researchers waited 30 days after the B2M injections and then ran the memory tests, the young mice showed no memory deficit. To determine the effects of removing B2M, the team engineered the mice to knock out the gene for the protein. With age, these animals showed less memory dysfunction than nonengineered mice of the same age (Nat. Med. 2015, DOI: 10.1038/nm.3898). “The implication here is if you could reduce B2M in humans, you could reverse age-related memory decline, which would be profound,” Small says.— MICHAEL TORRICE
JULY 13, 2015
