Microwaving deltamethrin can renew the insecticide’s ability to kill mosquitoes that have become resistant to it. Scientists are working to add the improved insecticide to bed nets, Tina Hesman Saey reported in “Restoring an insecticide’s mosquito-killing power” (SN: 6/17/23, p. 4).
Deltamethrin is so commonly used as an insecticide because it’s much more lethal for insects than it is for mammals, says Bart Kahr, a crystallographer at New York University. The lethal dose for a human, which is based on toxicology data for rats, would be more than 100 billion times what it is for a mosquito, he says.
Since microwaving deltamethrin changes its crystal structure but not its chemical composition, the lethal dose would not be expected to change, Kahr says. The new form might be faster at delivering deltamethrin to both humans and mosquitoes, but it would still take incredibly prolonged contact with a high amount of the insecticide to be consequential to a mammal. “Of course, no one has made such an experiment, but it stands to reason from the data that we have,” he says.
Brain implants in four people with chronic pain revealed a potential biomarker of the debilitating condition. The brain signal could one day help doctors track treatment responses, Laura Sanders reported in “Implants track chronic pain in the brain” (SN: 6/17/23, p. 10).
2023-08-11 05:00:00
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