When a reporter with the Sierra Club magazine asked Graham Peaslee, a physicist at the University of Notre Dame, to test several different samples of unused menstrual underwear for per- and polyfluoroalkyl substances (PFAS) in 2019, the results fueled concern over chemical exposure in feminine hygiene products — which ultimately ended up in a $5 million lawsuit against the period and incontinence underwear brand Thinx.

Then in 2023, the New York Times asked Peaslee to test 44 additional period and incontinence products for PFAS, a class of toxic fluorinated compounds inherently repellent to oil, water, soil and stains, and known as “forever chemicals” for their exceptionally strong chemical and thermal stability. Measurable PFAS were found in some layers of many of the products tested — some low enough to suggest the chemicals may have transferred off packaging materials, while others contained higher concentrations, suggesting the chemicals were intentionally used during the manufacturing process.

In the meantime, another group of researchers published a study that found PFAS in single-use period products, leading Peaslee and his lab to widen their investigation into all sorts of reusable feminine hygiene products — often viewed as an eco-friendly option by consumers. Now, the results of that study have been published in Environmental Science & Technology Letters.

Hydrogen fluoride (HF) is the simplest and cheapest fluorinating reagent available, but its volatility and toxicity limit its practical use. Now, researchers from Shibaura Institute of Technology, Japan, introduce a new approach for the generation of HF, which is both safe and scalable. Using the cation exchange method between Potassium fluoride (KF) and Amberlyst 15DRY, they generated HF and converted it to amine-3HF complexes, thereby expanding the range of accessible complexes for fluorination reactions.

Solar cells and computer chips need silicon layers that are as perfect as possible. Every imperfection in the crystalline structure of a silicon wafer increases the risk of reduced efficiency or defective switching processes. If you know how silicon atoms arrange themselves to form a crystal lattice on a thin surface, you gain fundamental insights into controlling crystal growth. To this end, a research team from the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), the University of Duisburg-Essen and the Canadian University of Alberta analyzed the behavior of silicon that was flash-frozen. The results show that the speed of cooling has a major impact on the structure of silicon surfaces (DOI: 10.1103/rmc4-xqb3). The underlying mechanism may also have occurred during phase transitions in the early universe shortly after the Big Bang.

Scientists tackle one of the most challenging problems in physics--the interplay between quantum theory and gravity—from a different angle.

SAN ANTONIO — July 21, 2025 — NASA’s Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites (TRACERS) mission, a collaborative effort led by the University of Iowa (UI) with substantial contributions from Southwest Research Institute (SwRI), has entered its final integration phase. NASA is set to launch TRACERS’ two satellites into low Earth orbit on July 22nd from Vandenberg Space Force Base in California. The TRACERS mission will explore the dynamic interactions between the Sun’s and Earth’s magnetic fields.