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This benchmark study evaluates deep learning-based molecular generative models on various polymer datasets. Selected models were further refined with reinforcement learning to generate hypothetical heat-resistant polymers. 

We collected extensive small molecule compounds from GDB-17, GDB-13, and PubChem and selected polymerization reaction pathways for eight types of polymers, to generate hundreds of quadrillions of hypothetical polymer structures. 

Voids—the nothingness—broadly exist within nanomaterials and impact properties ranging from catalysis to mechanical response. However, understanding nanovoids is challenging due to lack of imaging methods with the needed penetration depth and spatial resolution. Here, we integrate electron tomography, morphometry, graph theory and coarse-grained molecular dynamics simulation to study the formation of interconnected nanovoids in polymer films and their impacts on permeance and nanomechanical behaviour. Using polyamide membranes for molecular separation as a representative system, three-dimensional electron tomography at nanometre resolution reveals nanovoid formation from coalescence of oligomers, supported by coarse-grained molecular dynamics simulations. Void analysis provides otherwise inaccessible inputs for accurate fittings of methanol permeance for polyamide membranes. Three-dimensional structural graphs accounting for the tortuous nanovoids within, measure higher apparent moduli with polyamide membranes of higher graph rigidity. Our study elucidates the significance of nanovoids beyond the nothingness, impacting the synthesis‒morphology‒function relationships of complex nanomaterials. 

Abstract The Indonesian seas, with their complex passages and vigorous mixing, constitute the only route and are critical in regulating Pacific–Indian Ocean interchange, air–sea interaction, and global climate events. Previous research employing remote sensing and numerical simulations strongly suggested that this mixing is tidally driven and localized in narrow channels and straits, with only a few direct observations to validate it. The current study offers the first comprehensive temporal microstructure observations in the south of Lombok Strait with a radius of 0.05° and centered on 115.54^oE and 9.02^oS. Fifteen days of tidal mixing observations measured potential temperature and density, salinity, and turbulent energy dissipation rate. The results revealed significant mixing and verified the remotely sensed technique. The south Lombok temporal and depth averaged of the turbulent kinetic energy dissipation rate, and the diapycnal diffusivity from 20 to 250 m are$$\varepsilon$$ $\epsilon$ = 4.15 ± 15.9) × 10^–6W kg^–1and$$K\rho$$ $K\rho$= (1.44 ± 10.7) × 10^–2m²s^–1, respectively. This$$K\rho$$ $K\rho$is up to 10⁴times larger than the Banda Sea [$$K\rho$$ $K\rho$ = (9.2 ± 0.55) × 10^–6m²s^–1] (Alford et al. Geophys Res Lett 26:2741–2744, 1999) or the “open ocean”$$K\rho$$ $K\rho$= 0.03 × 10^–4 m²s⁻¹within 2° of the equator to (0.4–0.5) × 10^–4m²s⁻¹at 50°–70° (Kunze et al. J Phys Oceanogr 36:1553–1576, 2006). Therefore, nonlinear interactions between internal tides, tidally induced mixing, and ITF plays a critical role regulating water mass transformation and have strong implications to longer-term variations and change of Pacific–Indian Ocean water circulation and climate. 

Abstract Biofilms are ubiquitous surface-associated bacterial communities embedded in an extracellular matrix. It is commonly assumed that biofilm cells are glued together by the matrix; however, how the specific biochemistry of matrix components affects the cell-matrix interactions and how these interactions vary during biofilm growth remain unclear. Here, we investigate cell-matrix interactions inVibrio cholerae, the causative agent of cholera. We combine genetics, microscopy, simulations, and biochemical analyses to show thatV. choleraecells are not attracted to the main matrix component (Vibriopolysaccharide, VPS), but can be attached to each other and to the VPS network through surface-associated VPS and crosslinks formed by the protein Bap1. Downregulation of VPS production and surface trimming by the polysaccharide lyase RbmB cause surface remodeling as biofilms age, shifting the nature of cell-matrix interactions from attractive to repulsive and facilitating cell dispersal as aggregated groups. Our results shed light on the dynamics of diverse cell-matrix interactions as drivers of biofilm development. 

Polydimethylsiloxane is an important polymeric material with a wide range of applications. However, environmental effects like low temperature can induce crystallization in the material with resulting changes in its structural...