Chelation-Based Route to Aluminum-Free Layered Transition Metal Carbides (MXenes).

MXenes are of much interest because of their electrochemical, electronic, and surface chemical properties that arise from their structure and stoichiometry. The integrity and the nature of the terminal groups on the basal planes of MXene sheets depend strongly on the method used to etch the parent MAX (M = transition metal, A = Al, X = C, N, B) compound. Aluminum removal typically involves a high concentration of aqueous HF, HCl/LiF mixtures, or fluoride solutions of strong acids.

Modeling Percolation in Polymer Nanocomposites by Stochastic Microstructuring.

A methodology was developed for the prediction of the electrical properties of carbon nanotube-polymer nanocomposites via Monte Carlo computational simulations. A two-dimensional microstructure that takes into account waviness, fiber length and diameter distributions is used as a representative volume element. Fiber interactions in the microstructure are identified and then modeled as an equivalent electrical circuit, assuming one-third metallic and two-thirds semiconductor nanotubes.

Neuronal differentiation patterns in the optic tectum of the lizard Gallotia galloti.

This study examines in detail the sequences of morphological differentiation and deduces mode of migration into specific layers of all types of neurons present in the optic tectum of the lizard Gallotia galloti. It complements previous similar work on tectal histogenesis in the chick. It was found that the neuronal population diversity in the lizard tectum can be reduced by developmental analysis to three neuroblast classes, called Types I, II and III.