Recent progress in research on Fe(3)O(4) nanocrystals has attracted much attention both for investigating fundamental nanomagnetism and their potential applications in nanocatalysis, biosensing, magnetic resonance imaging (MRI) contrast agents and drug delivery. In this feature article, we provide an overview of synthetic strategies and growth mechanisms of various Fe(3)O(4) nanostructures, discuss the uniqueness of associated properties, and illustrate their potential applications.

Octahedral Fe(3)O(4) nanoparticles, showing ferrimagnetic behavior, were synthesised by a facile route and due to their monodispersity and anisotropic shape the nanoparticles self-assemble to superlattices with well-defined orientation.

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Hydrogels that combine the integrated attributes of being adhesive, self-healable, deformable, and conductive show great promise for next-generation soft robotic/energy/electronic applications. Herein, we reported a dual-network polyacrylamide (PAAM)/poly­(acrylic acid) (PAA)/graphene (GR)/poly­(3,4-ethylenedioxythiophene):poly­(styrene sulfonate) (PEDOT:PSS) (MAGP) conductive hydrogel composed of dual-cross-linked PAAM and PAA as well as PEDOT:PSS and GR as a conducting component that combines these features. A wearable strain sensor is fabricated by sandwiching the MAGP hydrogels between two dielectric carbon nanotubes (CNTs)/poly­(dimethylsiloxane) (PDMS) layers, which can be utilized to monitor delicate and vigorous human motion. In addition, the hydrogel-based sensor can act as a deformable triboelectric nanogenerator (D-TENG) for harvesting mechanical energy. The D-TENG demonstrates a peak output voltage and current of 141 V and 0.8 μA, respectively. The D-TENG could easily light 52 yellow-light-emitting diodes (LEDs) simultaneously and demonstrated the capability to power small electronics, such as a hygrometer thermometer. This work provides a potential approach for the development of deformable energy sources and self-powered strain sensors.

The electronic structures of charged carbon nanotube cluster models were calculated with the densityfunctional-theory ͑DFT͒ method. With the increasing number of extra electrons, ͑a͒ a potential barrier is formed near the tube wall; its height increases and the width at the highest occupied molecular-orbital ͑HOMO͒ level decreases; ͑b͒ the HOMO energy increases linearly, giving chances to electrons to tunnel through the barrier and escape; ͑c͒ the total energy first decreases and then increases, presenting a perfect parabolic curve and indicating an optimum number of extra electrons; and ͑d͒ electrical field near the tube was worked out. A comparison between the tube and a perfect conductor demonstrates some of their resemblances, but the exact properties such as the tube capacitance depend on the quantum theory calculations. The totalenergy variation obeys Koopmans' theorem and although calculated with DFT method, it can be expressed in terms of the tube's classical parameters such as capacitance and work function. The electronic charge rearrangement after the addition of extra electrons is presented and this might be the determinant of the electronic structures of charged carbon nanotubes.

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As a substitute for methyl bromide, effects of allyl isothiocyanate (AITC) on nontarget microorganisms in soil are poorly understood. This study measured the half-life of AITC in the soil as well as its effects on the soil substrate-induced respiration (SIR) and on communities of soil bacteria and fungi. The results showed that AITC had a short half-life and a short-term inhibition of SIR; high-throughput sequencing analysis showed that AITC had less effect on bacterial than fungal communities. Fumigation reduced the diversity of soil bacteria temporarily, but stimulated the diversity of soil fungi in the long-term and significantly changed the structure of the fungal community. Following AITC fumigation there were significant increases in the relative abundance of probiotics such as Sphingomonas, Streptomyces, Hypocreales, Acremonium, Aspergillus, and Pseudallescheria that help to control plant diseases. Our study provided useful information for assessing the ecological safety of AITC.

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