Lane formation in a driven attractive fluid

We investigate nonequilibrium lane formation in a generic model of a fluid with attractive interactions, that is, a two-dimensional Lennard-Jones fluid composed of two particle species driven in opposite directions. Performing Brownian dynamics simulations for a wide range of parameters, supplemented by a stability analysis based on dynamical density functional theory, we identify generic features of lane formation in the presence of attraction, including structural properties. In fact, we find a variety of states (as compared to purely repulsive systems), as well as a close relation between laning and long-wavelength instabilities of the homogeneous phase such as demixing and condensation.

Chemical Replacement of Noggin with Dorsomorphin Homolog 1 for Cost-Effective Direct Neuronal Conversion

The direct conversion of adult human skin fibroblasts (FBs) into induced neurons (iNs) represents a useful technology to generate donor-specific adult-like human neurons. Disease modeling studies rely on the consistently efficient conversion of relatively large cohorts of FBs. Despite the identification of several small molecular enhancers, high-yield protocols still demand addition of recombinant Noggin. To identify a replacement to circumvent the technical and economic challenges associated with Noggin, we assessed dynamic gene expression trajectories of transforming growth factor-β signaling during FB-to-iN conversion. We identified ALK2 (ACVR1) of the bone morphogenic protein branch to possess the highest initial transcript abundance in FBs and the steepest decline during successful neuronal conversion. We thus assessed the efficacy of dorsomorphin homolog 1 (DMH1), a highly selective ALK2-inhibitor, for its potential to replace Noggin. Conversion media containing DMH1 (+DMH1) indeed enhanced conversion efficiencies over basic SMAD inhibition (tSMADi), yielding similar βIII-tubulin (TUBB3) purities as conversion media containing Noggin (+Noggin). Furthermore, +DMH1 induced high yields of iNs with clear neuronal morphologies that are positive for the mature neuronal marker NeuN. Validation of +DMH1 for iN conversion of FBs from 15 adult human donors further demonstrates that Noggin-free conversion consistently yields iN cultures that display high βIII-tubulin numbers with synaptic structures and basic spontaneous neuronal activity at a third of the cost.