A UNSW-led study demonstrates how a new tool can detect blue whale calls with almost 100% accuracy, despite only being trained on one sample song. The tool has the potential to transform how scientists analyse rare and elusive species.

New research from the Mork Family Department of Chemical Engineering and Materials Science at USC Viterbi shows how the organization of electrons can reshape how a material responds to light – opening previously inconceivable possibilities for optical and quantum technologies.

Streamlining the synthesis of valuable amines, researchers present a new method that can selectively insert nitrogen into specific carbon–hydrogen bonds. According to their study, the approach could simplify drug development by enabling more efficient, scalable, and late-stage construction of carbon–nitrogen bonds from common chemical feedstocks. Incorporating nitrogen into organic molecules is a key step in synthesizing a host of chemicals used in pharmaceutical, agrochemical, and polymer industries. For example, amines – compounds which contain carbon-nitrogen (C-N) bonds – are widely used in prescribed drugs for their roles in enhancing bioavailability and target-binding interactions of active pharmaceutical ingredients. Amines are typically made from pre-modified and often expensive starting materials. A more efficient approach is to directly replace a carbon–hydrogen (C-H) bond with a nitrogen-containing group, which reduces waste and simplifies the synthesis process. However, this is difficult because most C–H bonds in a molecule have very similar reactivity, making it hard to target a single bond. To address these limitations, Tuan Anh Trinh and colleagues developed a bulky ligand bearing three pyridyl groups that forms a complex with silver triflimide salt, creating a catalytic system that can deliver a nitrene (a single monovalent nitrogen atom) from chiral sulfur(VI) nitrene precursors to a specific C-H bond within a target molecule. According to the authors, the method is compatible with readily available nitrene sources, making it suitable for scalable production of amines from common chemical feedstocks. It also supports late-stage installation of C-N bonds, a valuable feature in medicinal chemistry because it allows rapid generation and refinement of drug candidates. “The approach of Trinh et al. offers amination of a wide range of substrates independent of the electronic characteristics of their C–H bonds,” writes Radim Hrdina in a related Perspective. “Nevertheless, several parameters can be further optimized to reach better efficiency and selectivity.”

New high-altitude measurements have revealed a hidden population of extremely small, organic-rich aerosol particles in the lower stratosphere. The findings suggest that these ultrafine aerosols, likely lofted from the underlying troposhpere, are far more abundant and chemically influential than previously understood. The stratospheric aerosol layer, extending from roughly 8 to 35 kilometers above Earth’s surface, plays a crucial role in regulating climate by reflecting sunlight and enabling chemical reactions that influence atmospheric composition. Yet, despite its importance, our understanding of its constituent particles remains incomplete, largely because existing instruments struggle to detect the smallest particles, which fall below their sensitivity thresholds. It’s thought that extremely small particles from the lower atmosphere are transported into the stratosphere through processes such as tropical uplift, atmospheric mixing, intense storm systems, wildfire-driven convection, and even aircraft emissions. However, detailed information about their size distribution, which is critical for determining their volume, surface area, and role in chemical processes, has remained scarce.

 

Using data collected by a high-altitude research aircraft during the NASA Stratospheric Aerosol Processes, Budget, and Radiative Effects (SABRE) project in 2023, Ming Lyu and colleagues report detailed measurements of stratospheric particles ranging from 0.003 to 2.4 microns, capturing both their distribution and chemical compositions in regions up to 19 kilometers above Earth. In their analysis, Lyu et al. reveal notably high concentrations of extremely small, organic-rich aerosol particles, particularly in atmospheric regions influenced by recently transported air and within the polar vortex. Despite being exceptionally small, these particles dominate the surface area available for heterogeneous atmospheric chemistry and act as a significant condensation sink. Lyu et al. confirmed that many of these fine organic-rich particles originate from the lower atmosphere and subsequently interact with larger sulfur-based aerosols, including those formed from volcanic emissions. This interaction produces a complex, bimodal particle size distribution that current climate models fail to accurately reproduce.