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August 11, 2025—A supersticky gel that could be used in surgery, an incredibly bitter taste that is new to science and how to watch the Perseids meteor shower. —Robin Lloyd, Contributing Editor | | | | |
A first-of-its-kind analysis of compounds found in a shelf-like mushroom called bitter bracket has revealed an incredibly bitter taste that is new to science. The mushrooms tastes so unpleasant that it is considered inedible despite being nontoxic. Using an "artificial tongue" made of human taste receptors inserted into embryonic kidney cells, the scientists identified one substance so bitter that it registered even at a very low concentration, 63.3 micrograms per liter. "That's like sensing three quarters of a cup of sugar in an Olympic-sized swimming pool," writes freelance journalist K.R. Callaway. | | Why this matters: Bitter taste research in humans is only partially explored, despite the ubiquity of the flavor. Scientists have not yet discovered the natural activator of four of the more than 20 kinds of bitter taste receptors lining our mouths, throats, lungs, digestive tract and brain. Insights into these activating compounds could shed light on the evolution of our taste receptors. | | What the experts say: "Taste in your mouth does so much more than just perception," says physiologist Nirupa Chaudhari, who was not involved in the study. For example, taste can trigger the release of insulin and the production of stomach acid. | | Alexander Kurlovich/Alamy Stock Photo | | | | |
- It's fine to use an AI to try to solve math problems, but trustworthy results must be fully precise and justify every step in the chain-of-thought, writes Johns Hopkins University mathematician Emily Riehl. Several AI models recently succeeded in solving International Math Olympiad problems but the results could not be validated. And the olympiad problems are not of the type that professional mathematicians tackle. | 6 min read
| | The Tower of Hanoi consists of a small board on which three identical cylindrical rods are mounted. On the left rod there are five disks of different sizes with a hole in the middle. They are ordered by size, with the largest disk at the bottom. The goal of the game is to move all the disks from the left rod to the right rod in as few moves as possible. In each move, only one disk can be taken from one rod and placed on another rod, and a larger disk can never be placed on a smaller disk. How many and which moves are necessary to transport the disks? Click here for the solution. | | Most years at this time, I remember to step outdoors before bedtime to look up in the sky for Perseids. Last night's view was hazy, so I'm not confident that I saw a single shooting star. I could blame waning gibbous moonlight or streetlights. But I've seen Perseids, as well as less bold meteor showers, under similar conditions in past years. I'll try again tonight. Let us know if you catch the Perseids. Your note might include an estimate of the number of meteors per hour. Scientific American editor Clara Moskowitz writes you could spot between 5o to 100 meteors hourly.
| | —Robin Lloyd, Contributing Editor
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