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Abstract Our understanding of the assembly timeline of the Milky Way has been transforming along with the dramatic increase in astrometric and spectroscopic data available over the past several years. Many substructures in chemo-dynamical space have been discovered and identified as the remnants of various galactic mergers. To investigate the timeline of these mergers, we select main-sequence turnoff and subgiant stars (MSTOs) from the H3 survey, finding members in seven metal-poor components of the halo: Gaia-Sausage/Enceladus (GSE), the Helmi Streams, Thamnos, Sequoia, Wukong/LMS-1, Arjuna, and I’itoi. We also select out a metal-poor in situ population to facilitate comparison to the evolution of the Milky Way itself at these early epochs. We fit individual isochrone ages to the MSTOs in each of these substructures and use the resulting age distributions to infer simple star formation histories (SFHs). For GSE, we resolve an extended SFH that truncates ≈10 Gyr ago, as well as a clear age–metallicity relation. From this age distribution and measured SFH we infer that GSE merged with the Milky Way at a time 9.5–10.2 Gyr ago, in agreement with previous estimates. We infer that the other mergers occurred at various times ranging from 9 to 13 Gyr ago, and that the metal-poor in situ Galaxy built up within only a few billion years. These results reinforce the emerging picture that both the disk and halo of the Milky Way experienced a rapid assembly. 

Peripheral nerve modulation via electrical stimulation shows promise for treating several diseases, but current approaches lack selectivity, leading to side effects. Exploring selective neuromodulation with commercially available nerve cuffs is impractical due to their high cost and limited spatial resolution. While custom cuffs reported in the literature achieve high spatial resolutions, they require specialized microfabrication equipment and significant effort to produce even a single design. This inability to rapidly and cost-effectively prototype novel cuff designs impedes research into selective neuromodulation therapies in acute studies. To address this, we developed a reproducible method to easily create multi-channel epineural nerve cuffs for selective fascicular neuromodulation. Leveraging commercial flexible printed circuit (FPC) technology, we created cuffs with high spatial resolution (50 μm) and customizable parameters like electrode size, channel count, and cuff diameter. We designed cuffs to accommodate adult mouse or rat sciatic nerves (300–1500 μm diameter). We coated the electrodes with PEDOT:PSS to improve the charge injection capacity. We demonstrated selective neuromodulation in both rats and mice, achieving preferential activation of the tibialis anterior (TA) and lateral gastrocnemius (LG) muscles. Selectivity was confirmed through micro-computed tomography (μCT) and quantified through a selectivity index. These results demonstrate the potential of this fabrication method for enabling selective neuromodulation studies while significantly reducing production time and costs compared to traditional approaches. 

Background Nanoparticles (NPs) hold promise as alternatives to antibiotics in the fight against multi-drug-resistant bacteria. However, concerns about their cytotoxicity, particularly their effects on mammalian cells, must be thoroughly addressed to ensure therapeutic safety. Amphiphilic Janus NPs, which have segregated hydrophobic and polycationic ligands on two hemispheres, have previously been shown to exhibit potent antibacterial activity. Methods In this study, we evaluated the cytotoxicity of amphiphilic Janus NPs in immune and cancer cell lines. Cytotoxicity assays were performed to assess the effects of Janus NPs on cell viability and membrane integrity, with a particular focus on how internalization of the nanoparticles influenced cellular responses. Results The results revealed that both immune and cancer cells exhibited negligible cytotoxic effects when exposed to Janus NPs. However, phagocytic immune cells demonstrated greater susceptibility to membrane damage and viability loss, suggesting that internalization plays a significant role in nanoparticle-induced cytotoxicity. Conclusions Amphiphilic Janus NPs show great potential as highly effective antibacterial agents with minimal cytotoxicity. While immune cells may be more vulnerable to nanoparticle-induced damage due to their internalization capacity, these findings support the further investigation of Janus NPs for clinical applications.