Enhancing Mechanical Properties of Graphene/Aluminum Nanocomposites via Microstructure Design Using Molecular Dynamics Simulations.

This study explores the mechanical properties of graphene/aluminum (Gr/Al) nanocomposites through nanoindentation testing performed via molecular dynamics simulations in a large-scale atomic/molecular massively parallel simulator (LAMMPS). The simulation model was initially subjected to energy minimization at 300 K, followed by relaxation for 50 ps under the NPT ensemble, wherein the number of atoms (N), simulation temperature (T), and pressure (P) were conserved. After the model was fully relaxed, loading and unloading simulations were performed. This study focused on the effects of the Gr arrangement with a brick-and-mortar structure and incorporation of high-entropy alloy (HEA) coatings on mechanical properties. The findings revealed that Gr sheets (GSs) significantly impeded dislocation propagation, preventing the dislocation network from penetrating the Gr layer within the plastic zone. However, interactions between dislocations and GSs in the Gr/Al nanocomposites resulted in reduced hardness compared with that of pure aluminum. After modifying the arrangement of GSs and introducing HEA (FeNiCrCoAl) coatings, the elastic modulus and hardness of the Gr/Al nanocomposites were 83 and 9.5 GPa, respectively, representing increases of 21.5% and 17.3% compared with those of pure aluminum. This study demonstrates that vertically oriented GSs in combination with HEA coatings at a mass fraction of 3.4% significantly enhance the mechanical properties of the Gr/Al nanocomposites.

Sustainability outcomes and policy implications: Evaluating China's "old urban neighborhood renewal" experiment.

Globally, old urban neighborhood transformation has become a new urban sustainability focus for its significant contribution to the United Nation's Sustainable Development Goal 11. A regeneration-oriented approach is particularly important for Chinese cities with a dwindling land supply, obsoleting infrastructure, and inadequate standard of living. Using a mixed-methods approach informed by BREEAM Communities, we examined two Chinese initiatives-old urban neighborhood renewal (OUNR) and sponge city development (SCD)-through a comprehensive study of pilot project sustainability, policy emphases and gaps, and broader governance implications. We found that SCD's top-down technocratic management was highly efficient in enhancing neighborhood hydrological functions and physical environment. However, successes were undermined by the lack of climate considerations and civic participation. Besides actionable recommendations for applied scholarship and policymaking in China, we provide insight into how the OUNR/SCD initiatives may broadly inform worldwide urban regeneration practices through project and policy experimentations that build adaptive capacity.

Exploring the Interaction Mechanism Between Cyclopeptide DC3 and Androgen Receptor Using Molecular Dynamics Simulations and Free Energy Calculations.

Androgen receptor (AR) is a key target in the discovery of anti-PCa (Prostate Cancer) drugs. Recently, a novel cyclopeptide Diffusa Cyclotide-3 (DC3), isolated from Hedyotisdiffusa, has been experimentally demonstrated to inhibit the survival and growth of LNCap cells, which typically express T877A-mutated AR, the most frequently detected point mutation of AR in castration-resistant prostate cancer (CRPC). But the interaction mechanism between DC3 and AR is not clear. Here in this study we aim to explore the possible binding mode of DC3 to T877A-mutated AR from molecular perspective. Firstly, homology modeling was employed to construct the three-dimensional structure of the cyclopeptide DC3 using 2kux.1.A as the template. Then molecular docking, molecular dynamics (MD) simulations, and molecular mechanics/generalized Born surface area (MM-GBSA) methods were performed to determine the bind site and explore the detailed interaction mechanism of DC3-AR complex. The obtained results suggested that the site formed by H11, loop888-893, and H12 (site 2) was the most possible position of DC3 binding to AR. Besides, hydrogen bonds, hydrophobic, and electrostatic interactions play dominant roles in the recognition and combination of DC3-AR complex. The essential residues dominant in each interaction were specifically revealed. This work facilitates our understanding of the interaction mechanism of DC3 binding to AR at the molecular level and contributes to the rational cyclopeptide drug design for prostate cancer.

Neighborhood design and walking. A quasi-experimental longitudinal study.

BACKGROUND: Few studies have employed longitudinal data to examine associations between the physical environment and walking. METHODS: Using cross-sectional (n=70) and longitudinal (n=32) data (collected 2003-2006), associations of neighborhood design and demographics with walking were examined. Participants were low-income, primarily African-American women in the southeastern U.S. Through a natural experiment, some women relocated to neo-traditional communities (experimental group) and others moved to conventional suburban neighborhoods (control group). RESULTS: Post-move cross-sectional comparisons indicated that women in neo-traditional neighborhoods did not, on average, walk more than women in suburban neighborhoods. Race and household size were significant predictors of physical activity. Additionally, using longitudinal data, this study controlled for the effects of pre-move walking and demographics. Analyses examined the effects of environmental factors (e.g., density, land-use mix, street-network patterns) on post-move walking. Women who moved to places with fewer culs-de-sac, on average, walked more. Unexpectedly, increases in land-use mix were associated with less walking. CONCLUSIONS: Results suggest that neo-traditional neighborhood features alone (e.g., sidewalks, front porches, small set-back distances) may not be enough to affect walking; however, changes in street patterns may play a role.