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Abstract Stellar streams from disrupted globular clusters are dynamically cold structures that are sensitive to perturbations from dark matter subhalos, allowing them in principle to trace the dark matter substructure in the Milky Way. We model, within the context of Λ cold dark matter, the likelihood of dark matter subhalos to produce a significant feature in a GD-1-like stream and analyze the properties of such subhalos. We generate many realizations of the subhalo population within a Milky Way mass host halo using the semianalytic codeSatGen, accounting for effects such as tidal stripping and dynamical friction. The subhalo distributions are combined with a GD-1-like stream model, and the impact of subhalos that pass close to the stream are modeled withGala. We find that subhalos with masses in the range 2 × 10⁶M_⊙–10⁸M_⊙at the time of the stream–subhalo encounter, corresponding to masses of about 2 × 10⁷M_⊙–10⁹M_⊙at the time of infall, are the likeliest to produce gaps in a GD-1-like stream. We find that gaps occur on average ∼3 times per realization of the host system. These gaps have typical widths of ∼(5–27)° and fractional underdensities of ∼(10–30)%, with larger gaps being caused by heavier subhalos. The stream–subhalo encounters responsible for these have impact parameters (0.1–1.5) kpc and relative velocities ∼(200–410) km s⁻¹. We also investigate the effects of increasing the host-halo mass on the gap properties and formation rate. 

Understanding the mechanisms of molecular transport in polyamide membranes is imperative to improve their solute-specific selectivity. We explored the partitioning behaviors of water and salts in polyamide membranes to elucidate the role of ion-membrane interactions in the transport. Quartz crystal microbalance (QCM) was employed to quantify the mass uptake at different temperatures and determine partition energies (Ek) for water and salts under two different pH values. Zeta potential and permeability tests were conducted to support the ionmembrane affinity trends observed with QCM and link these trends to ion-ion selectivity. Our results demonstrate a high affinity of water to the polyamide membrane (Ek < 0), with a significant swelling effect attributed to dipole interactions and hydrogen bonding. Ion partitioning revealed distinct differences between monovalent and divalent cations, as well as between kosmotropic and chaotropic anions. Specifically, divalent cations (Ca2+ and Mg2+) exhibited considerably lower partition energies (-0.99 and 0.29 kcal mol-1, respectively) and more efficient charge neutralization, indicating stronger interactions with the membrane compared to monovalent cations (~2.2 kcal mol-1). The partition energies of the chaotropic iodide and kosmotropic sulphate anions were substantially different (-5.5 and 4.0 kcal mol-1, respectively), likely due to the different tendency of these anions to shed their hydration shell and stick to the polymer. Last, our permeability tests indicate the potential existence of an intrinsic tradeoff between ion partitioning and intrapore diffusion, presumably due to the opposite effects that ion-membrane interactions have on these transport steps. Overall, our work underscores the role of ionspecific interactions in membrane transport and selectivity. 

Full Changelog: https://github.com/ponder-lab/Common-Eclipse-Refactoring-Framework/compare/v5.0.0...v5.1.0