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In nature, biological compartments such as cells rely on dynamically controlled permeability for matter exchange and complex cellular activities. Likewise, the ability to engineer compartment permeability is crucial for in vitro systems to gain sustainability, robustness, and complexity. However, rendering in vitro compartments such a capability is challenging. Here, a facile strategy is presented to build permeability-configurable compartments, and marked advantages of such compartmentalization are shown in reconstituting sustained synthetic biology systems in vitro. Through microfluidics, the strategy produces micrometer-sized layered microgels whose shell layer serves as a sieving structure for biomolecules and particles. In this configuration, the transport of DNAs, proteins, and bacteriophages across the compartments can be controlled an guided by a physical model. Through permeability engineering, a compartmentalized cell-free protein synthesis system sustains multicycle protein production; ≈100 000 compartments are repeatedly used in a five-cycle synthesis, featuring a yield of 2.2 mg mL-1 . Further, the engineered bacteria-enclosing compartments possess near-perfect phage resistance and enhanced environmental fitness. In a complex river silt environment, compartmentalized whole-cell biosensors show maintained activity throughout the 32 h pollutant monitoring. It is anticipated that permeability-engineered compartmentalization should pave the way for practical synthetic biology applications such as green bioproduction, environmental sensing, and bacteria-based therapeutics.

Short-term probabilistic forecasts of the trajectory of the COVID-19 pandemic in the United States have served as a visible and important communication channel between the scientific modeling community and both the general public and decision-makers. Forecasting models provide specific, quantitative, and evaluable predictions that inform short-term decisions such as healthcare staffing needs, school closures, and allocation of medical supplies. Starting in April 2020, the US COVID-19 Forecast Hub (https://covid19forecasthub.org/) collected, disseminated, and synthesized tens of millions of specific predictions from more than 90 different academic, industry, and independent research groups. A multimodel ensemble forecast that combined predictions from dozens of groups every week provided the most consistently accurate probabilistic forecasts of incident deaths due to COVID-19 at the state and national level from April 2020 through October 2021. The performance of 27 individual models that submitted complete forecasts of COVID-19 deaths consistently throughout this year showed high variability in forecast skill across time, geospatial units, and forecast horizons. Two-thirds of the models evaluated showed better accuracy than a naïve baseline model. Forecast accuracy degraded as models made predictions further into the future, with probabilistic error at a 20-wk horizon three to five times larger than when predicting at a 1-wk horizon. This project underscores the role that collaboration and active coordination between governmental public-health agencies, academic modeling teams, and industry partners can play in developing modern modeling capabilities to support local, state, and federal response to outbreaks.

In order to provide technical support and evaluation basis for the development of remediation technology of radioactive contaminated sites and the site selection, design and construction of radioactive waste disposal facilities, the reliable longterm risk assessment for potential nuclear waste repositories and decommissioning of nuclear facilities requires detailed knowledge on the migration behavior of radionuclides in natural, it is necessary to understand the reaction mechanism of radionuclides in the complex geological environment of aquifers. The batch experiments and dynamic undisturbed soil column migration experiments of 90Sr, 137Cs, 238Pu and 241Am were carried out under saturated steadystate flow conditions in fine sand column, a theoretical model of nuclide migration in soil and groundwater environment was constructed, and the irreversible adsorption reaction mechanism of the microinterface was studied through static adsorptiondesorption and dynamic undisturbed soil column migration experiments, and the environmental migration flux of nuclides was calculated. The static adsorption and desorption experiments adopt batch method, and the test medium is fine sand with saturated porous media from an arid mining area in Gansu Province. The fine sand and soil samples according to the solidliquid ratio of 1 g∶9 mL were added into the centrifuge tube, and the nuclide activity concentration was measured after adsorption and desorption equilibriums to obtain the adsorption and desorption isotherms. Dynamic column method used undisturbed soil to ensure the continuity of soil sample medium, original connectivity of void channels and authenticity of stratum. The design and advantages of dynamic column method is to take into account various physical, chemical and biogeochemical reaction processes and complex migration paths of tracers during migration in soil. And the dynamic migration and transformation process of 90Sr, 137Cs, 238Pu and 241Am were studied in saturated porous media with anisotropic timevarying hydrologic characteristics by artificial spraying under controlled laboratory initial conditions and boundary conditions. The results show that the absorption isotherm of 90Sr doesn’t coincide with its desorption isotherm, with an angle at 3238° between them. According to the metastable equilibrium adsorption theory, 90Sr has an irreversible adsorptiondesorption process, and ions exchange is the dominated action for its adsorption. As for 137Cs, 238Pu and 241Am, reversible adsorptiondesorption process are shown, and their adsorptions are mainly attributed to surface complexation. Equilibrium adsorption theory and nonequilibrium adsorption model can be used to describe the migration peak phenomenon of different nuclides in the dynamic soil column experiment, which can be effectively integrated into chemical nonequilibrium and physical nonequilibrium processes. Considering the superposition of convectiondispersion and chemical reaction on solute migration, solute migration equations were established based on the reaction rate equation, and the calculated and measured concentration distribution curves were fitted reasonably to obtain a reaction model that can accurately describe and predict nuclide migration. As for 90Sr, the nonequilibrium adsorption model by transport column was taken into account the firstorder rate coefficient (β) between the dissolved phase and the adsorbed phase. The calculated concentration distribution curve is good agreement with the measured concentration. The fitting results show that the distribution coefficient (Kd) and β of 90Sr in the fine sand aquifer are 085 mL/g and 016 h-1, respectively, in terms of 137Cs, 238Pu and 241Am, the radionuclides concentration distribution curves in equilibrium adsorption and nonequilibrium models are in good agreement with the measured values. Meanwhile the calculated results by two different adsorption models are almost similar, and the Kd are 49×102, 21×104, and 6.0×103 mL/g for 137Cs, 238Pu and 241Am. It shows that the stronger adsorption capacities of the nuclides have the faster rate of the adsorption-desorption in the soil, meanwhile the shorter time for the system reaction equilibrium. At this time, the fitting results of the equilibrium adsorption mode and the nonequilibrium adsorption mode are closer to each other.

Precise prediction of phase diagrams in molecular dynamics simulations is challenging due to the simultaneous need for long time and large length scales and accurate interatomic potentials. We show that thermodynamic integration from low-cost force fields to neural network potentials trained using density-functional theory (DFT) enables rapid first-principles prediction of the solid–liquid phase boundary in the model salt NaCl. We use this technique to compare the accuracy of several DFT exchange–correlation functionals for predicting the NaCl phase boundary and find that the inclusion of dispersion interactions is critical to obtain good agreement with experiment. Importantly, our approach introduces a method to predict solid–liquid phase boundaries for any material at an ab initio level of accuracy, with the majority of the computational cost at the level of classical potentials. [ABSTRACT FROM AUTHOR]

Understanding how nanoparticles deform under compression not only is of scientific importance but also has practical significance in various applications such as tribology, nanoparticle-based probes, and the dry grinding of raw materials. In this study, we conducted compression tests on model brittle glassy nanoparticles using molecular dynamics simulations. We found that during the early stages of plastic deformation, shear bands formed in a similar pattern regardless of the nanoparticle size. However, as the deformation continued, dominant cracks emerged in large nanoparticles while being suppressed in smaller ones. This size-dependent brittle-to-ductile transition can be explained by a simple model based on Griffith's theory. We also investigated the effect of the surface stress state on fracture using thermally tempered nanoparticles. We observed that the presence of compressive surface stress strengthened the nanoparticle by suppressing crack formation, even when a pre-notch was present. On the other hand, tensile surface stress had the opposite effect. Interestingly, nanoparticles with both tensile and compressive surface stress promoted shear deformation, which could potentially compromise the mechanical performance of tempered glass despite delayed crack formation. [ABSTRACT FROM AUTHOR]

After the accident at the Fukushima nuclear power plant in Japan, a large amount of radioactive contaminated soil was generated, which brought great challenges for treating and disposing of the soil. The recycling of slightly polluted soil can reduce the amount of contaminated soil. This paper analyzes the main exposed scenes of 137Cs polluted soil used in the construction of highway subgrade, soil bag handling and paving. The Monte Carlo algorithm (MCNP) and RESRAD-ONSITE program are used to simulate the two scenes respectively, and the concentration of 137Cs is derived in the soil at the effective dose of 1 mSv per year. It is concluded that: the annual effective doses of porter and paver are 0.41 mSv per year and 0.23 mSv per year respectively caused by 1 Bqg-1 137Cs contaminated soil; the activity of 137Cs are 2.44 Bqg-1 and 4.26 Bqg-1 respectively in the soil at 1 mSv per year for porter and paver; the calculated results are consistent with those reported by the Japan Atomic Research Agency. Also, they are lower than the activity concentration corresponding to the effective dose control level of 1 mSv per year under low-probability events in IAEA No. RS-G-1.7 slightly.