Volume 9 Issue 10, October 2010

Mexico's economy is doing relatively well, but its science is chronically under-supported and the country's technological dependence is increasing rapidly. Without a strong science and technology base, the nation's future is at risk.

Despite the good education of its scientists, science and technology in Mexico faces multiple challenges, says Juan Ramón de la Fuente, a former Minister of Health and former Rector of the National Autonomous University of Mexico.

The discovery of a highly resistive ferrite magnet where a low magnetic field induces a ferroelectric polarization at room temperature is a key advance towards applications of magnetoelectric coupling.

Using a micropatterning technique, the architecture of actin networks is revealed to be influenced by the spatial organization of actin filament nucleation. Considering the geometric boundaries within live cells, implications in the realm of actin-induced cell functions are vast.

Flexible arrays of transducers can now be fabricated with pressure sensitivity and response times approaching those of natural human skin.

The topological nature of a certain type of grain boundary in polycrystalline graphene may be used to tailor the electrical transport properties.

The mechanisms by which chemically functionalized carbon nanotubes flow in blood and are excreted through the kidneys illustrate the unconventional behaviour of these fibrillar nanostructures, and the opportunities they offer as components for the design of advanced delivery vehicles.

Only few magnetoelectric materials, where magnetism and ferroelectricity are coupled, are known to exist at room temperature, and in most cases the magnetoelectric coupling is weak. The discovery of strong room-temperature magnetoelectric coupling in Sr₃Co₂Fe₂₄O₄₁ at low magnetic fields is therefore a significant advance towards the practical application of multiferroics.

In magnetoelectric compounds, magnetism and ferroelectricity are coupled. The observation of light-induced size changes in the room-temperature magnetoelectric BiFeO₃ now adds optical functionality to magnetoelectric devices that may lead to new applications arising from the coupling of light, electric and magnetic fields.

Graphene films are usually made from domains with different orientations. How does this affect transport? A theory of charge transmission through graphene grain boundaries now predicts two distinct transport behaviours depending on the grain-boundary structure. The results could provide important information for the design of efficient graphene-based electronic devices.

The typical high-surface-area and voids of nanoscale cage structures make them attractive for catalysis, gas storage and drug delivery. Contrary to other metal–semiconductor particles, a ruthenium cage is now shown to grow selectively on the edges of a faceted copper sulphide nanocrystal.

Polymeric impurities in liquid crystals are known to perturb liquid-crystalline order. It is now shown that spatial gradients in the order, created by illuminating the materials with ultraviolet light, can be used to generate forces that allow the polymers to be concentrated or dispersed in the liquid crystal.

Flexible electronic devices should lead to new practical applications. Parallel arrays of inorganic nanowires have now been integrated into a flexible pressure-sensor array on a macroscopic scale. The sensor array operates at low voltage and acts as an artificial electronic skin, sensing pressure profiles with high spatial resolution.

Actin filaments are a principal component of the cell cytoskeleton. Using micropatterning methods, physical influences on the growth of highly ordered actin structures are investigated. The spatial organization of actin nucleation sites is discovered to play an important role in establishing the architecture of actin networks.

Using optical antennas in optoelectronic devices could lead to improved device performance. Photoemission from the inner core of core–shell single-walled nanotube structures where the optical bandgap of the core is smaller than that of the outer shells demonstrates that these structures channel excitons thereby acting as optical concentrators.

Typically, electronic contributions have a very small effect on infrared absorption in solids. Now, however, a giant-infrared-absorption band of electronic origin has been observed in reduced graphene oxide. The band arises from the coupling of electronic states to the asymmetric stretch mode of a yet-unreported structure, consisting of oxygen atoms aggregated at edges of defects.

Proton conductor oxides are promising materials for their use as electrolytes for reducing the operation temperature of solid-oxide fuel cells. Epitaxially oriented yttrium-doped barium zirconate films now show unprecedented proton conductivity in the 500–700 °C range.

The selective reaction of one part of a bifunctional molecule is a fundamental challenge in heterogeneous catalysis. Modifying a supported palladium catalyst with alkanethiol self-assembled monolayers is now shown to increase selectivity for the hydrogenation of 1-epoxy-3-butane to 1-epoxybutane.

Flexible organic electronics could eventually be used to create electronic skin. Films of a pressure-sensitive microstructured elastomer are now used as the dielectric layer in organic field-effect transistors to create highly sensitive devices. The elastomer is also used in a matrix pressure sensor that can detect loads in numerous positions.

Mexico is a country rich with natural resources and an educated workforce. Yet its scientific output remains below its potential. In a focus issue we highlight some of Mexico's structural problems.