The arcuate fasciculus is a white-matter fiber tract that is involved in human language. Here we compared cortical connectivity in humans, chimpanzees and macaques (Macaca mulatta) and found a prominent temporal lobe projection of the human arcuate fasciculus that is much smaller or absent in nonhuman primates. This human specialization may be relevant to the evolution of language.

A novel method for producing nanosized Na2ZrO3 with well-controlled crystal phase has been developed, resulting in excellent kinetics for CO2 capture at high temperatures. The novel preparation method involves a soft-chemical route starting with the generation of a complex from zirconoxy nitrate and sodium citrate, followed by a strong exothermic reaction between nitrate and citrate during calcination in a controlled atmosphere. The in situ produced carbon during the calcination serves as a dispersant of the oxide, and subsequent carbon burnoff promotes the formation of nanocrystalline Na2ZrO3 with an open pore structure. The calcination temperature and atmosphere are very crucial for controlling the crystal phase of Na2ZrO3. The resulting sodium zirconate samples are characterized by XRD, N2 adsorption, Hg porosimetry, and SEM. A two-step calcination at 1073 K results mainly in the monoclinic phase, whereas one-step calcination at 1073 K or higher enhances the formation of the thermodynamically stable phase, namely hexagonal Na2ZrO3. A kinetic study of CO2 capture in a tapered element oscillating microbalance (TEOM) reactor has shown that the monoclinic Na2ZrO3 is much more active than its hexagonal counterpart. The ability to work at CO2 partial pressures as low as 0.025 bar, together with the excellent stability in multicycle capture/regeneration makes nanocrystalline Na2ZrO3 a very promising CO2 acceptor for different applications.

Calcium silicate hydrate (C−S−H) is a mesoporous amorphous material with water confined in the gel pores, which provides the medium for investigating the structure, dynamics, and mechanical properties of the ultraconfined interlayer water molecules. In this study, C−S−H gels with different compositions expressed in terms of the Ca/Si ratio are characterized in the light of molecular dynamics. It is found that with increasing Ca/Si ratio, the molecular structure of the silicate skeleton progressively transforms from an ordered to an amorphous structure. The calcium silicate skeleton, representative of the substrate, significantly influences the adsorption capability, reactivity, H-bond network, and mobility of the interlayer water molecules. The structures were tested for mechanical properties by simulated uniaxial tension, and the mechanical tests associated with structural analysis reveal that the stiffness and cohesive force of C−S−H gel is weakened by both breakage of silicate chains and penetration of water molecules. In addition, the reactive force field is coupled with both the mechanical response and chemical response during the large tensile deformation process. On the one hand, the silicate chains, acting in a skeletal role in the layered structure, depolymerize to enhance the loading resistance. On the other hand, water molecules, attacking the Si−O and Ca−O bonds, dissociate into hydroxyls, which are detrimental to the cohesive force development.

No abstract

No abstract