The Magnetoelectric (ME) effect has been observed in single phase hexaferrite bulk and thin films of SrCo2Ti2Fe8O19. In this paper we demonstrate that the ME linear coupling depends strongly on the Co ion concentration relative to the Ti ion concentration exhibiting extremum points at a concentration consistent with above formula. The Alternating Target Laser Ablation Deposition technique was utilized to deposit ME hexaferrite films for the first time. This allows for the deposition of transition metal ions at specific sites in the basic unit cell of the hexaferrite.

In the recent years, several investigators are incorporating nanotechnology, one of the most powerful trendsetters in material research, to conventional polymer prepregs to enhance mechanical properties of composite strucutures. The current paper outlines the role of nanotechnology in reinforcing resin and challenges for fabricating nanomaterial reinforced prepregs. As delamination is the most critical problem for composite materials, the current study only focuses the application nanotechnology as a possible solution to alleviate delamination problems in laminated composites. The importance of nanoengineered prepregs is discussed in a viewpoint of improvement in interlaminar properties of the laminated composite materials.

Recent years have seen an increased application of small-scale uniaxial testing—microcompression—to the study of plasticity in macroscopically brittle materials. By suppressing fast fracture, new insights into deformation mechanisms of more complex crystals have become available, which had previously been out of reach of experiments. Structurally complex intermetallics, metallic compounds, or oxides are commonly brittle, but in some cases extraordinary, though currently mostly unpredictable, mechanical properties are found. This paper aims to give a survey of current advances, outstanding challenges, and practical considerations in testing such hard, brittle, and anisotropic crystals.

Due to the recent outbreak of the Zika virus (ZIKV) in several regions, rapid, and accurate methods to diagnose Zika infection are in demand, particularly in regions that are on the frontline of a ZIKV outbreak. In this paper, three diagnostic methods for ZIKV are considered. Viral isolation is the gold standard for detection; this approach can involve incubation of cell cultures. Serological identification is based on the interactions between viral antigens and immunoglobulin G or immunoglobulin M antibodies; cross-reactivity with other types of flaviviruses can cause reduced specificity with this approach. Molecular confirmation, such as reverse transcription polymerase chain reaction (RT–PCR), involves reverse transcription of RNA and amplification of DNA. Quantitative analysis based on real-time RT–PCR can be undertaken by comparing fluorescence measurements against previously developed standards. A recently developed programmable paper-based detection approach can provide low-cost and rapid analysis. These viral identification and viral genetic analysis approaches play crucial roles in understanding the transmission of ZIKV.

Recent observations on strength and deformation of small metals containing microstructures, including dislocation patterns, grain boundaries, and second-phase precipitates are reviewed. These microstructures impose an internal length scale that may interplay with the extrinsic length scale due to the specimen size to affect strength and deformation in an intricate manner. For micro-crystals containing pre-existing dislocations, Taylor work-hardening may dictate the dependence of strength on specimen size. The presence of grain boundaries in a small specimen may lead to effects far from the conventional Hall–Petch behavior. Precipitate–dislocation interactions in a small specimen may lead to an interesting weakest-size behavior.

Melanin (from the Greek μέλας, mélas, black) is a biopigment ubiquitous in flora and fauna, featuring broadband optical absorption, hydration-dependent electrical response, ion-binding affinity as well as antioxidative and radical-scavenging properties. In the human body, photoprotection in the skin and ion flux regulation in the brain are some biofunctional roles played by melanin. Here we discuss the progress in melanin research that underpins emerging technologies in energy storage/conversion, ion separation/water treatment, sunscreens, and bioelectronics. The melanin research aims at developing approaches to explore natural materials, well beyond melanin, which might serve as a prototype benign material for sustainable technologies.

Sodium-ion batteries (SIBs) have received intensive attentions owing to the abundant and inexpensive sodium (Na) resource. Layered vanadium oxides are featured with various valence states and corresponding compounds, and through multi-electron reaction they are capable to deliver high Na storage capacity. The rational construction of unique structures is verified to improve their Na storage properties. This perspective provides an overview of recent advances in layered vanadium oxide for SIBs, with a particular focus on construction of novel nanostructures, and mechanism studies via in situ characterization. Finally, we predict possible breakthroughs and future trends that lie ahead for high-performance layered vanadium oxides SIBs cathode.

Partially reduced graphene oxide functionalized with Fe nanoparticles alone or combined with Au and Pt nanoparticles is synthesized and characterized, and their effects on Polymer Electrolyte Membrane Fuel Cell (PEMFC) power output and carbon monoxide resistance are tested. Samples were prepared with various combinations of metal nanoparticles to create a cost-effective catalyst. Transmission and scanning electron microscopy revealed metal nanoparticles embedded on graphene sheets, some with magnetic susceptibility. PEMFC tests exhibited power output that was >180% of the control in a pure H2 gas feed and 250% of the control in a H2 gas feed with 1000 ppm of CO.

We discuss relationships between transparent supercapacitor performance and the morphology of its ZnO nanostructured electrodes. The electrodes with different morphologies were prepared by magnetron sputtering and postdeposition annealing. They were decorated with MnO2 nanostructures and tested in symmetric transparent supercapacitors. The capacitances for discharging at 10 µA/cm2 were in the range of 20–53 µF/cm2, meaning that an increase of 250% in capacitance can be obtained by optimizing the electrode morphology. Optimal morphologies were hierarchical with a large range of pore sizes available. The worst performing had the smallest range of pore sizes. Best devices exhibited transparencies above 90%.

A hydrothermal method was developed to synthesize Ag–Pt nanoparticles with controlled surface composition where formaldehyde (HCHO) was utilized as a directing agent. Transmission electron microscopy and powder x-ray diffraction characterizations showed no change in bulk composition and phases as well as the size and morphology of as-made bimetallic nanocrystals. X-ray photoelectron spectroscopy study revealed, however, the enrichment of Pt on the surface as the amount of HCHO used increased. This chemically driven change in surface composition represents a nontraditional approach in the control of synthesis of bimetallic nanoparticle catalysts. A close relationship between catalytic performance and surface composition of these Ag–Pt nanocrystals was observed for electrochemical oxidation of formic acid.

Biomaterials with antibacterial activity are widely developed for the treatment of bone infection. In the present study, hydroxyapatite (HAp) nanorods were prepared by green synthesis using Azadirachta indica and Coccinia grandis leaf extract. The prepared samples were characterized by various characterization techniques and the results indicate that the prepared samples are constituted of phase pure polycrystalline HAp having hexagonal crystal structure. Moreover, antibacterial activity test confirm that the HAp prepared using leaf extract as a solvent having significant antibacterial activity against Escherichia coli and Staphylococcus aureus. Hence, green synthesis can be a prospective way to develop orthopedic biomaterials with antibacterial properties.

The hydrobaric effect on photoactivity of titanium dioxide (TiO2) fabricated by cathodic deposition in an aqueous solution was evaluated in this study. When the applied pressure was increased to 35 MPa, the water-splitting performance was improved by almost fourfold of the performance of the TiO2 prepared at atmospheric pressure. The surface states effect was significant in the deposited TiO2, which was exploited to affect the charges recombination of TiO2, and thereby enhance the resultant photoelectrochemical water-splitting performance. The hydrobaric cathodic deposition could be extended to fabrication of other metal oxides to eliminate the negative influence from the high-temperature process.

The effect of tellurium (Te) doping on the electrocatalytic activity of La1−x Te x MnO3 toward the oxygen reduction reaction is investigated for the first time. La1−x Te x MnO3 with x-values up 23% were synthesized from a single ionic liquid-based precursor, yielding nanoparticles with mean diameter in the range of 40–68 nm and rhombohedral unit cell. Electrochemical studies were performed on carbon-supported particles in alkaline environment. The composition dependence activity is discussed in terms of surface density of Mn sites and changes in the effective Mn oxidation state.

We report on the intermediate-temperature synthesis (973 K) and operation (<750 K) of Ce4.67(SiO4)3O-based thin-film oxy-apatites. The apatite thin films show the high conductivity of ~0.05–0.5 S/cm and excellent stability in reducing atmosphere (<10−17 atm), which makes promising these materials as anodes for intermediate-temperature solid oxide fuel cell (SOFC) application. The proto-type SOFCs implementing single-layer apatite and apatite/Pt bilayer anodes were fabricated and the resulting performance (e.g., peak power density of ~5 mW/cm2 at 748 K) presents notable feasibility of ZCS-based oxy-apatite anodes for thin-film SOFC devices.

Nickel oxide-based materials have attracted significant interest for a variety of energy conversion applications although many of their structures remain unresolved. In this study, Density Functional Theory+U (DFT+U) and hybrid DFT calculations are used to analyze the properties of crystalline nickel oxyhydroxide (β-NiOOH) with hydrogen (H) vacancies. Hydrogen vacancies are found to lower the band gap without creating states inside the band gap. Inter-layer crossing is a possible transport pathway, while intra-layer transport is inhibited. Bulk modulus is not influenced by H vacancies in the crystal. β-NiOOH with H vacancies exhibits good electronic properties, essential for solid electrolytes and anodes in solid oxide fuel cells.

Starting from polydisperse diatomaceous earth (DE), we proposed an efficient separation method for obtaining different morphologies of biosilica from diatoms. DE is a very low-cost source of silica containing all the differently nanostructured elements. By a glucose gradient/dialysis, three types of biosilica morphologies were achieved: rods, valves, and clusters. We fully characterized the diatom fractions and we used them to produce fluorescent biosilica platforms (“tabs”). These supports exhibited good resistance in water, ethanol, and soft scraping. A preliminary biologic application by testing Saos-2 proliferation was also performed to check osteoblasts-like cells biologic attitude for this scaffolds with tunable nanostructure.

Several methods for determination of elastic–plastic parameters by instrumented spherical indentation tests have been presented in the past few years. Each method was established according to a specific constitutive model. Identification of the constitutive models of new materials has become an indispensable step in order to choose an appropriate indentation method to extract the elastic–plastic parameters. In the present work, the half depth energy accumulation rate and Meyer's index were related to the elastic–plastic constitutive models via qualitative and numerical analyses. A method for identification of the elastic–plastic constitutive models by instrumented spherical indentation test was proposed.

Cellular activity upon osmotic stress is related to the occurrence of several disease conditions. The real-time monitoring of the cell response to this kind of stress can give insight into the comprehension of mechanisms involved in cellular shrinkage. Currently the dynamics of the osmotic stress is studied using dedicated and tricky methodologies, not suited to the in vivo testing. We show that a disposable electronic device is very effective for studying the early stage of the osmotic stress induced on human lung adenocarcinoma cells, A549, by a hyperosmotic environment. Our findings corroborate the experimental results obtained by a standard complementary analysis.

In this study, we have developed a facile and simple route for preparation of ultrafine CoO/reduced graphene oxide (rGO) nanohybrids with tunable particle size and crystallinity for lithium-ion battery (LIB) application. At the optimized calcination time of 60 min, the homogeneous and ultrafine CoO nanoparticles with mean size of 4.5 nm can be intimately attached onto rGO surface to rapidly transport Li ions and electrons. The CoO/rGO exhibits excellent rate capability and high specific capacity of 520 mAh/g at 2400 mA/g. In addition, the capacity can be recovered to 900 mAh/g at 150 mA/g after 60 cycles, indicating the superior electrochemical performance of CoO/rGO for LIB applications.

Lithium-ion capacitors utilizing graphite (G) and reduced graphite oxide (RGO) as negative electrode materials were investigated. Various reduction methods of graphite oxide were applied to compare properties of modified materials. The hybrid cells showed the energy density at mild current regimes of ca. 70–100 Wh/kg. However, at higher rates, only the capacitor with chemically RGO maintained this tendency. Moreover, the system demonstrated the energy density of 34 Wh/kg at a power density of 26 kW/kg. The electrochemical measurements were conducted in three-electrode systems to record responses of positive and negative electrodes separately.