Opportunity-Rich Schools and Sustainable Communities: Seven Steps to Align High-Quality Education With Innovations in City and Metropolitan Planning and Development

Details challenges and steps for linking quality education and community and economic vitality, including establishing a shared vision and metrics, aligning investments for prosperity, and expanding access via transportation. Lists promising practices

Kinetics and mechanism of the formation of water cluster ions from O2(plus) and H2O in He, Ar, N2, and O2 at 296 K

The reaction sequence leading from O2(+) to H3O(+)-H2O was examined in He, Ar, N2 and O2 carrier gases in a flowing afterglow system. The rate constants for the reactions were measured and the kinetic analysis for their determination is presented. For M = N2, two new steps involving the formation and reaction of O2(+)-N2 were proposed and examined. The rate constants are discussed and compared with other experimental values

Deuterium Kinetic Isotope Effects in Microsolvated Gas-Phase E2 Reactions

This work describes the first experimental studies of deuterium kinetic isotope effects (KIEs) for the gas-phase E2 reactions of microsolvated systems. The reactions of F−(H2O)n and OH−(H2O)n, where n = 0, 1, with (CH3)3CX (X = Cl, Br), as well as the deuterated analogs of the ionic and neutral reactants, were studied utilizing the flowing afterglow-selected ion flow tube technique. The E2 reactivity is found to decrease with solvation. Small, normal kinetic isotope effects are observed for the deuteration of the alkyl halide, while moderately inverse kinetic isotope effects are observed for the deuteration of the solvent. Minimal clustering of the product ions is observed, but there are intriguing differences in the nature and extent of the clustering process. Electronic structure calculations of the transition states provide qualitative insight into these microsolvated E2 reactions

Collision rate constants for polarizable ions

AbstractLangevin described a model for the interaction between an ion and a neutral nearly a century ago and since then, many modifications have been introduced to adjust for specific circumstances. This work discusses the induced dipole–induced dipole interaction between an ion and a neutral without a permanent dipole and introduces an anisotropic adjustment. A point polarizable ion model (PPI) and an orientation dependent polarizable ion model (ODPI) are discussed and applied to systems where the ion is highly polarizable and the neutral is only weakly polarizable. Significant deviations from classical Langevin rate constants and significant differences between PPI and ODPI are observed

Weirdest Martensite: Smectic Liquid Crystal Microstructure And Weyl-poincaré Invariance

Smectic liquid crystals are remarkable, beautiful examples of materials microstructure, with ordered patterns of geometrically perfect ellipses and hyperbolas. The solution of the complex problem of filling three-dimensional space with domains of focal conics under constraining boundary conditions yields a set of strict rules, which are similar to the compatibility conditions in a martensitic crystal. Here we present the rules giving compatible conditions for the concentric circle domains found at two-dimensional smectic interfaces with planar boundary conditions. Using configurations generated by numerical simulations, we develop a clustering algorithm to decompose the planar boundaries into domains. The interfaces between different domains agree well with the smectic compatibility conditions. We also discuss generalizations of our approach to describe the full three-dimensional smectic domains, where the variant symmetry group is the Weyl-Poincaré group of Lorentz boosts, translations, rotations, and dilatations. © 2016 American Physical Society.1161

Modifications of Hyaluronan Influence the Interaction with Human Bone Morphogenetic Protein-4 (hBMP-4).

n this study, we have demonstrated that the modification of hyaluronan (hyaluronic acid; Hya) with sulfate groups led to different binding affinities for recombinant human bone morphogenetic protein-4 (rhBMP-4). The high-sulfated sHya2.8 (average degree of sulfation (D.S.) 2.8) exhibited the tightest interaction with rhBMP-4, followed by the low-sulfated sHya1.0, as determined with surface plasmon resonance (SPR), ELISA, and competition ELISA. Unmodified Hya, chondroitin-sulfate (CS), and heparan sulfate (HS) showed significantly less binding affinity. SPR data could be fitted to an A + B = AB Langmuir model and binding constants were evaluated ranging from 13 pM to 5.45 microM. The interaction characteristics of the differentially sulfated Hyas are promising for the incorporation of these modified polysaccharides in bioengineered coatings of biomaterials for medical applications