A general scaling rule for the collision energy dependence of a rotationally inelastic differential cross-section and its application to NO(X) plus He

International audienceThe quasi-quantum treatment (QQT) (Gijsbertsen et al., J. Am. Chem. Soc., 2006, 128, 8777) provides a physically compelling framework for the evaluation of rotationally inelastic scattering, including the differential cross sections (DCS). In this work the QQT framework is extended to treat the DCS in the classically forbidden region as well as the classically allowed region. Most importantly, the QQT is applied to the collision energy dependence of the angular distributions of these DCSs. This leads to an analytical formalism that reveals a scaling relationship between the DCS calculated at a particular collision energy and the DCS at other collision energies. This scaling is shown to be exact for QM calculated or experimental DCSs if the magnitude of the (kinematic apse frame) underlying scattering amplitude depends solely on the projection of the incoming momentum vector onto the kinematic apse vector. The QM DCSs of the NO(X)-He collision system were found to obey this scaling law nearly perfectly for energies above 63 meV. The mathematical derivation is accompanied by a mechanistic description of the Feynman paths that contribute to the scattering amplitude in the classically allowed and forbidden regions, and the nature of the momentum transfer during the collision process. This scaling relationship highlights the nature of (and limits to) the information that is obtainable from the collision-energy dependence of the DCS, and allows a description of the relevant angular range of the DCSs that embodies this information

Partitioning of cancer therapeutics in nuclear condensates

© 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. The nucleus contains diverse phase-separated condensates that compartmentalize and concentrate biomolecules with distinct physicochemical properties. Here, we investigated whether condensates concentrate small-molecule cancer therapeutics such that their pharmacodynamic properties are altered. We found that antineoplastic drugs become concentrated in specific protein condensates in vitro and that this occurs through physicochemical properties independent of the drug target. This behavior was also observed in tumor cells, where drug partitioning influenced drug activity. Altering the properties of the condensate was found to affect the concentration and activity of drugs. These results suggest that selective partitioning and concentration of small molecules within condensates contributes to drug pharmacodynamics and that further understanding of this phenomenon may facilitate advances in disease therapy11sci