At the 254th National Meeting and Exposition of the American Chemical Society, researchers are presenting a low-cost, portable, paper-based sensor that can let you know when to toss food and cosmetics. The sensor can detect antioxidants in tea and wine, and be used to explore remote locations, such as the Amazon rainforest, in search of natural sources of antioxidants. "I've always been interested in developing technologies that are accessible to both industry and the general population," Silvana Andreescu, Ph.D., says. "My lab has built a versatile sensing platform that incorporates all the needed reagents for detection in a piece of paper. At the same time, it is adaptable to different targets, including food contaminants, antioxidants and free radicals that indicate spoilage." Phys.Org reports: What sets Andreescu's sensors apart from others, she says, are the nanostructures they use to catch and bind to compounds they're looking for. "Most people working on similar sensors use solutions that migrate on channels," Andreescu says. "We use stable, inorganic particles that are redox active. When they interact with the substances we want to detect, they change color, and the intensity of the change tells us how concentrated the analyte is." Additionally, because all of the reagents needed to operate the device are incorporated in the paper, users don't need to add anything other than the sample being tested. The American Chemical Society has published a video detailing the sensor. Their paper has been published in the journal Analyst.

Fascinating article on The New Yorker about how the Voyager Golden Record was made: The Voyagers' scientific mission will end when their plutonium-238 thermoelectric power generators fail, around the year 2030. After that, the two craft will drift endlessly among the stars of our galaxy -- unless someone or something encounters them someday. With this prospect in mind, each was fitted with a copy of what has come to be called the Golden Record. Etched in copper, plated with gold, and sealed in aluminum cases, the records are expected to remain intelligible for more than a billion years, making them the longest-lasting objects ever crafted by human hands. We don't know enough about extraterrestrial life, if it even exists, to state with any confidence whether the records will ever be found. They were a gift, proffered without hope of return. I became friends with Carl Sagan, the astronomer who oversaw the creation of the Golden Record, in 1972. He'd sometimes stop by my place in New York, a high-ceilinged West Side apartment perched up amid Norway maples like a tree house, and we'd listen to records. Lots of great music was being released in those days, and there was something fascinating about LP technology itself. A diamond danced along the undulations of a groove, vibrating an attached crystal, which generated a flow of electricity that was amplified and sent to the speakers. At no point in this process was it possible to say with assurance just how much information the record contained or how accurately a given stereo had translated it. The open-endedness of the medium seemed akin to the process of scientific exploration: there was always more to learn.