Electrical interactions between bacteria and the environment are delicate and essential. In this study, an external electrical current is applied to capacitive titania nanotubes doped with carbon (TNT-C) to evaluate the effects on bacteria killing and the underlying mechanism is investigated. When TNT-C is charged, post-charging antibacterial effects proportional to the capacitance are observed. This capacitance-based antibacterial system works well with both direct and alternating current (DC, AC) and the higher discharging capacity in the positive DC (DC+) group leads to better antibacterial performance. Extracellular electron transfer observed during early contact contributes to the surface-dependent post-charging antibacterial process. Physiologically, the electrical interaction deforms the bacteria morphology and elevates the intracellular reactive oxygen species level without impairing the growth of osteoblasts. Our finding spurs the design of light-independent antibacterial materials and provides insights into the use of electricity to modify biomaterials to complement other bacteria killing measures such as light irradiation.

In this work, we treat the Poisson-Nernst-Planck (PNP) equations as the basis for a consistent framework of the electrokinetic effects. The static limit of the PNP equations is shown to be the charge-conserving Poisson-Boltzmann (CCPB) equation, with guaranteed charge neutrality within the computational domain. We propose a surface potential trap model that attributes an energy cost to the interfacial charge dissociation. In conjunction with the CCPB, the surface potential trap can cause a surface-specific adsorbed charge layer σ. By defining a chemical potential μ that arises from the charge neutrality constraint, a reformulated CCPB can be reduced to the form of the Poisson-Boltzmann equation, whose prediction of the Debye screening layer profile is in excellent agreement with that of the Poisson-Boltzmann equation when the channel width is much larger than the Debye length. However, important differences emerge when the channel width is small, so the Debye screening layers from the opposite sides of the channel overlap with each other. In particular, the theory automatically yields a variation of σ that is generally known as the "charge regulation" behavior, attendant with predictions of force variation as a function of nanoscale separation between two charged surfaces that are in good agreement with the experiments, with no adjustable or additional parameters. We give a generalized definition of the ζ potential that reflects the strength of the electrokinetic effect; its variations with the concentration of surface-specific and surfacenonspecific salt ions are shown to be in good agreement with the experiments. To delineate the behavior of the electro-osmotic (EO) effect, the coupled PNP and Navier-Stokes equations are solved numerically under an applied electric field tangential to the fluid-solid interface. The EO effect is shown to exhibit an intrinsic time dependence that is noninertial in its origin. Under a step-function applied electric field, a pulse of fluid flow is followed by relaxation to a new ion distribution, owing to the diffusive counter current. We have numerically evaluated the Onsager coefficients associated with the EO effect, L 21 , and its reverse streaming potential effect, L 12 , and show that L 12 ¼ L 21 in accordance with the Onsager relation. We conclude by noting some of the challenges ahead.

BiFeO 3 (BFO) films deposited on SrTiO3 (001) substrates and on LaNiO3-coated SrTiO3 (001) substrates with different annealing ambiences of oxygen and nitrogen were studied by using micro-Raman spectroscopy and x-ray diffraction (XRD). XRD showed that the films are in single-phase with rhombohedral structure. According to the analysis of the group theory, 13 Raman-active modes, which can be classified as 4A1 and 9E modes, have been observed in the BiFeO3 films. Raman spectra along the growth direction of the BFO films in the side-view scattering geometry were performed by the Raman mapping technique. The variations of Raman shift and Raman bandwidth in different depths of the films imply the existence of residual strain along the growth direction of the BFO films. These results are very useful for the understanding of the depth dependence of the physical properties including the interface and surface structure of the BFO films.

In this Communication, we have demonstrated a facile and effective approach to identify the structure of the superlong well-aligned single-walled carbon nanotubes (SWNTs) by the combination of electrodeposition of metal (Ag) with Raman spectroscopy. The suitable density and the visibility of the Ag-deposited long oriented nanotubes make it possible to acquire Raman spectra from isolated individual nanotubes very easily. The results reveal that the well-oriented SWNT arrays on SiO2/Si wafer fabricated by EtOH chemical vapor deposition using Fe/Mo nanoparticles as catalyst exhibit a low percentage of metallic SWNTs (5%). Among other SWNTs about 62.3% are semiconducting SWNTs, and a small amount of nanotubes are quasimetallic. About 32% are a so-called quasi-insulator, which is caused inevitably by the defects during growth. Furthermore, the structural uniformity of the long SWNTs can be also evaluated by the deposition of Ag along the length and Raman spectroscopy. This method also provides an approach to deposit other metals on long SWNTs, which could have various potential applications such as for use as sensors, etc. More importantly, this facile method can be applied to long SWNT arrays fabricated from other different catalytic systems so that the relationship between the growth conditions and the structures of SWNTs are expected to be ruled out.

Systematic studies of as-grown MnAs films deposited by molecular-beam epitaxy on GaAs(001) and GaAs(113)A reveal that their magnetic properties and, in particular, their saturation magnetization are determined by the phase separation into stripes of ferromagnetic α-MnAs and paramagnetic β-MnAs. Using a specific saturation magnetization MS*, which refers to the actual volume of α-MnAs, the thickness dependence of MS* can be described in a universal way. It is due to the variation of the stripe structure and the changing of the intra- and interstripe magnetic interaction. Values well above ∼1100emu∕cm3, obtained for the optimum film thickness at room temperature, are considered as an intrinsic property of a nearly defect-free MnAs in the fully magnetized state.

Carbon is unique in the variety of configurations it can adopt with itself and other elements. Here we show how ion beams can be used to nanostructure various diamond polytypes, epitaxially aligning them to a silicon substrate. The ready controllability of ion beams, which are already used to manufacture submicrometre-scale devices, means that our findings should enable new carbon and non-carbon materials to be nanostructured for a host of applications.

Tellurium (Te) with a flower-like superstructure has been successfully synthesized through a low temperature biphasic solvothermal reaction utilizing diethyldithiocarbamato tellurium (IV) (TDEC) as Te source and 2,2 0 -dithiodibenzoic acid (DTBA) as a reducing agent. Characterizations by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscope (HRTEM), energy dispersive X-ray spectroscopy (EDS), selected-area electron diffraction (SAED) show that the as-prepared product consists of well-aligned needle-like t-Te nanorods growing radically from the core. These nanorods have a diameter ranging from tens to hundreds of nanometers and a length of several micrometers, and the Raman spectra are greatly affected by their diameter. Fluorescence measurement reveals that the t-Te superstructures produce blue-violet emission.

BACKGROUND: Bactrocera dorsalis is a devastating pest on fruits and vegetables because the adult female is the key factor that determines the population density of offspring and the degree of host damage. Unfortunately, there is still a lack of effective female attractants for behavioral control. Males of B. dorsalis fed on methyl eugenol (ME) were shown to be more sexually attracted to females and, therefore, were more successful in mating over ME-deprived males.RESULTS: In the current study, we demonstrated that (E)-coniferyl alcohol (E-CF), one of the ME metabolites in males, was highly attractive to sexually-mature females in laboratory bioassays. During the dusk courtship period, mature females showed the highest response to E-CF. However, there were no significant differences in olfactory responses to E-CF between virgin and mated mature females. Moreover, no obvious signs and symptoms of toxicity or death were observed in mice during a 14-day acute oral toxicity test. Toxicologically, no significant changes were observed in body weight, water intake, food consumption and absolute and relative organ weights between control and treated groups of healthy-looking mice, implying that E-CF could be regarded as non-toxic. Furthermore, cytotoxicity assessment revealed that E-CF was non-toxic against human fetal lung fibroblast 1 (HFL1), human breast cancer (MDA-MB-231), mouse embryonic hepatocytes (BNL-CL.2) and Spodoptera frugiperda ovary (SF-9) cell lines.CONCLUSIONS: E-CF proved to be an effective, promising and eco-friendly lure to B. dorsalis females. Therefore, this study may facilitate the development of novel control strategies against B. dorsalis in the field.